1

Discrepancies between objective findings and subjective state of health in the process of rehabilitation and their effects on health-

related quality of life

Reinhold Jagsch

Faculty of Psychology,

University of Vienna, Austria

Correspondence to:

Reinhold Jagsch

Liebiggasse 5/3rd floor A-1010 Vienna

Austria

Telephone: + 43 - 1 - 4277 – 478 93

Fax: + 43 - 1 - 4277 – 478 99

e-mail:reinhold.jagsch@univie.ac.at

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Summary. Background: This article provides an overview of studies in which

assessments of specific functional capacity, made by experts on the one hand

(objective) and by patients on the other (subjective) were compared in various patient

groups. In essence, these data reveal marginal or insignificant associations.

Methods: Based on these considerations, a theoretical differential-diagnosis model of

objective findings/subjective state of health is presented. By dichotomization of

specific functional capacity at these two levels, the model permits the classification of

a patient cohort into four sub-groups: Patients with concurrence between subjective

and objective assessments are referred to as “the fortunate” while those with a

negative concurrence are termed “the unfortunate”. In case of discrepancies between

these two levels, for instance when patients’ subjective assessment was good

although their condition was obviously poor, they are considered to be in a so-called

“disease paradox”. Alternatively, patients whose subjective assessment of their

condition was poor although the objective findings were positive, were considered to

be in a so-called “health dilemma”.

Results: The study in a sample of patients who had received an artificial hip joint for

mobility disorders revealed striking differences in health-related quality of life (HrQol).

Comparisons of HrQoL data pre- and post-operatively in the whole sample

demonstrated an improvement in five of six dimensions (loss of energy, pain,

emotional reaction, sleeping problems, and problems in physical mobility, p<0.01) of

the Nottingham Health Profile. Specifically, after grouping patients accordingly to the

proposed model striking positive changes in HrQoL were registered in patients of the

fortunate and disease paradox groups while the improvements in the health dilemma

and unfortunate groups were minimal.

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Conclusion: Timely identification of these patients in the process of rehabilitation

would significantly contribute to the achievement of a good health-related quality of

life for all patients.

Key words: Health-related quality of life, Nottingham Health Profile, functional

capacity, total hip arthroplasty

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Introduction

One of the first researchers who focused on this point of intersection between

medicine and clinical psychology and conducted a specific and comprehensive study

of the discrepancies between the judgments of medical experts and those of patients

in respect of their state of health was Myrtek (1998). In his theory of illness behavior,

Myrtek described a scheme of four categories consisting of two congruent groups

which he named healthy and ill persons in the medical sense. Apart from these, he

identified two discrepant groups which he assigned “inappropriate illness behavior”

(in 1978 Pilowsky had termed this phenomenon “abnormal illness behavior”).

Depending on their inclination, he named these groups “healthy ill persons” or “ill

healthy persons”, as evidenced by the title of his book.

A few years earlier, in 1991, Filipp and Ferring had made a similar formal

classification, a division into four categories. In their description of subjectivity and

objectivity in the determination of quality of life, they also distinguished between four

groups: In case of concurrence of subjective and objective evaluations of quality of

life they referred to the persons as “the fortunate”; in case of negative concurrence

the authors referred to the individuals as “the unfortunate”. In case of discrepancies

between these two levels, for instance when the individuals’ subjective assessment

was good although their objective state was evidently poor, these persons were

considered to be in a paradox situation, i.e. in a “satisfaction paradox”. Alternatively,

the individuals were deemed to be in a “dissatisfaction dilemma” when their

subjective assessment of their condition was poor despite the presence of positive

environmental factors (Figure 1).

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objective surrounding subjective evaluation of one´s own life

factors good bad good

the fortunate

dissatisfaction dilemma

bad

satisfaction paradox the unfortunate

Figure 1. Original scheme of Filipp and Ferring (1991) describing general quality of life.

These concepts were demonstrated by results from practical experience, based on a

psychological study of Brickman, Coates and Janoff-Bulman (1978). The authors

requested three groups of test persons to asses their state of happiness, i.e. their

subjective state. The first group consisted of lottery winners, the second of patients

who had suddenly been confronted with the diagnosis of paraplegia following a life-

threatening accident, and the third was a control group. An evaluation of the

assessments of their current status revealed that the patients’ subjective state was –

as expected – highly significantly poorer than that of the control group. However, it

was striking to note that the subjective state of lottery millionaires, apparently favored

by fortune, was hardly better than that of the control group. The probands’ prognostic

assessments of their state of health at a fictitious time-point in the near future (about

one year) were entirely unexpected for the layman: Despite extremely diverse

external environmental factors, the three groups gave nearly identical estimates of

their future subjective states.

Discrepancies between objective findings and subjective state of health in the health sector

Accordingly, several studies have shown that associations between doctors’

estimations of health-related stresses and the corresponding evaluations of patients

remain insignificant. In a large preventive study focusing on cardiovascular disease in

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middle-aged men, Robra, van der Heyden and Machens (1982) observed

pathologically elevated cholesterol and blood sugar levels in 20.7% and 12.0%,

respectively. Smoking and obesity are known to be major risk factors for

cardiovascular disease. However, if one considers the medical history and the state-

of-health data of the high-risk group, persons deemed to be at great risk reported

milder symptoms than did persons with no risk factors. The agreement between the

doctors’ estimations of the health status of middle-aged women and the women’s

own evaluations was reported to be 22% by a Swedish group; the authors

considered this value significant but low. Correlative associations between individual

symptoms and the estimations explained only 1 to 12% of the underlying variance

(Mellner & Lundberg, 2003). Similarly, objective stress values in a healthy population

showed only moderate agreement with the corresponding assessments obtained by

questionnaires (Lindholm, Brevinge, Bergh, Körner & Lundholm, 2003). This

phenomenon is observed in patients with physical disease as well: In a randomized

group of patients with different somatic diagnoses, Mabe, Hobson, Jones and Jarvis

(1988) requested the treating physicians to assess the severity of symptoms on a

seven-point Likert scale. A comparison of these assessments with those of patients

revealed a non-significant correlation value of 0.10; a large majority of the patients

over-estimated the severity of their symptoms. Michel, Kohlmann and Raspe (1997)

established a moderate agreement (kappa = 0.47) between the treating physicians

and the patients in respect of the severity of symptoms in a specific patient group

(back pain). Filipp and Ferring (1991) report an insignificant correlation coefficient of r

= 0.17 in a random sample of gastroenterological patients.

Confirmation of the presence of a wide discrepancy between the objective and the

subjective state of health reported by patients, and the theoretical models proposed

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for this phenomenon in the published literature, will be investigated here in order to

answer the following question: Is it possible to identify the above mentioned four

groups on the basis of the clinical condition (specific functional capacity) of patients in

the process of rehabilitation within a precisely defined cohort?

Explanation of terms

For the following study the above mentioned theoretical models were used and

modified as follows: The modified Viennese model was based on one variable that is

accessible to objective as well as subjective assessment, namely the so-called

specific functional capacity. What does “specific” functional capacity here mean; in

what way does it differ from a “general” functional capacity that may be present?

Owing to the Babylonian confusion of terms, which is frequently mentioned in the

literature (Leplege & Hunt, 1997) – Tully and Cantrill (1999) call it the “semantic

minefield” – a digression is given here, which delineates the medical and

psychological constructs used in this study.

The extent of “health-related quality of life” as determined by the patients was

selected as the outcome variable because, on the one hand, one of the goals of

rehabilitation is to improve the patient’s quality of life (Richter, Schwarz, Eisemann &

Bauer, 2003; WHOQoL Group, 1995) and, on the other hand, quality of life is

considered to be a dynamic construct that may change in the course of time, e.g.

when a critical event in life occurs or the patient undergoes a severe type of medical

treatment (Allison, Locker & Feine, 1997). The term quality of life actually originated

in the social sciences. It was coined in welfare economics in the beginning of the 20th

century. Quality of life achieved socio-political significance, especially in the USA,

from the mid-sixties of the last century. It entered Europe somewhat later, where it

was offered as an alternative to counter the pre-eminence of purely quantitative

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thought. In other words, purely economical indices were complemented by social

factors. In the health sector, the concept of quality of life research, i.e. the concept of

health-related quality of life became established only in the beginning of the

nineteen-eighties. Although one would presume that a subject like health-related

quality of life of patients should be of major importance in this sector, i.e. for medical

specialists, psychologists and health-care personnel, a scientific discussion about the

theory and measurement of this construct started rather late. After individual survey

instruments had been constructed and tested in practice, the last few years have

witnessed a revival, a kind of retrospective look at the theoretical and methodological

principles of quality of life research, coupled with considerations as to how such

research can be systematically integrated in the evaluation, quality assurance and

planning of future health care services (Bullinger, Ravens-Sieberer & Siegrist, 2000).

The reason is to be found in the indeterminateness and poor tangibility which

persisted for a long time around this construct. Quality of life is a construct that is

considered familiar by many because of its practical context, but has not been

scientifically defined until the present day. The importance of health-related quality of

life clearly lies in the fact that it has made a significant contribution to a

transformation – farther away from a purely mechanistic-physiological view of the

anonymous patient, and closer to a holistic appraisal of the individual. The main

points of focus of this concept are the individual, his/her thoughts and feelings, state

of health, and ability to cope with the disease (Rosenberg, 1995). Despite the

absence of a comprehensive and widely accepted definition, experts agree that

health-related quality of life must be regarded as a multi-dimensional construct

consisting of the following main components (Bullinger & Hasford, 1991):

physical state (general state, mobility, pain),

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psychological state (cognitive and emotional factors),

social integration (integration and social support), and

coping with activities of daily living (functional competence).

In this context, subjectivity, i.e. self-reports of patients is given emphasis. In fact, the

measurement of quality of life in health and illness is determined by the patient’s

subjective assessment (Bullinger et al., 2000; Majani, Giardini & Scotti, 2005; Ormel,

Lindenberg, Steverink & von Korff, 1997; Ravens-Sieberer, Cieza & Bullinger, 2001).

Both “functional competence” and various aspects of the “physical state” address

elements of the above mentioned term “functional capacity”. The basic distinction to

be made between the grouping variable (assignment of individual patients to the

experimental groups) and the dependent variable (outcome in respect of the health-

related quality of life of patients) is based on the two components “assessment level”

and “degree of generality”. In order to divide patients into the four categories

mentioned above, one would have to use a construct that allows the evaluation of

specific functional impairments (i.e. not general functions) at two levels (objective

versus subjective). Orthopedic experts have standardized calculation formulae which

they use to quantify behavior samples obtained in catamnestic investigations in order

to include, or weight, several factors like limitations in flexion or joint mobility in the

overall evaluation. On the other hand, these disabilities or limitations can be

subjectively evaluated by the patients themselves. The patient is asked to provide

information on these subjects by the use of targeted questions in specific functional

questionnaires. Thus, the first condition is the possibility to evaluate the same

construct (specific functional capacity) simultaneously from a subjective viewpoint (by

the patient) and from the external viewpoint (a trained expert who has extensive

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experience). With the help of appropriate operationalization, it should be possible to

identify discrepancies or agreements/concordances between objective findings

(objective assessment of the expert) and subjective states of health (subjective

assessment of the progress of rehabilitation by the patient himself/herself). The

second condition is that a multi-dimensional concept of evaluation should be applied

for the outcome. It may include functional aspects (such as those in the survey of

quality of life) but, in terms of its concept, should address function (or functional

limitations which have been empirically proven to aggravate, for instance with

advancing age) at a general level. The following examples of items from the

investigation instruments will demonstrate this distinction in a descriptive way: The

item “I can move only within the house” (item 10 of the quality of life questionnaire

known as the Nottingham Health Profile) investigates the ability “physical mobility” at

a general level, non-specifically, with the options “yes” versus “no”, while the question

“Can you stand for 30 minutes without interruption (e.g. in a queue)?” (item 6 of the

Hannover functional questionnaire), a function that was impaired by the disease, is

inquired specifically, with the option of grading one’s response.

In a meta-analysis published in 1999, Smith, Avis and Assmann mention that the

terms “quality of life” and “health status” have often been used interchangeably, but

refer to two distinct concepts. Empirical evidence of the distinction between specific

functional capacity (as registered objectively by the expert and also subjectively by

the patient) and general functional aspects (such as those included in quality of life

questionnaires) was provided recently by Fritz and Piva (2003) from back pain

research. Using the Physical Impairment Index (PII) constructed by Waddell’s

research group (Waddell, Somerville, Henderson & Newton, 1992), a questionnaire

that investigates the “specific functional capacity” of back pain patients, Fritz and Piva

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(2003) studied aspects of reliability and validity in patients with acute symptoms. In

the course of this investigation the authors were able to establish a significant

correlation of r = 0.43 (explained variance, 18.5%) for both instruments that measure

“specific functional capacity” at both levels of assessment (objective versus

subjective). The correlation between PII and the physical component score of the

quality of life instrument SF-36 was significant at the level of 5%, but poorly relevant

with a coefficient of r = 0.28 (explained variance, 7.8%), while the correlation with the

mental component score was r = 0.00.

A prerequisite at the theoretical level, in order to conduct such empirical studies in

the field of objective findings/subjective state of health, is that the construct used to

assign patients to the respective groups according to concordant or discrepant

judgments must be specific and also accessible to objective and subjective

assessment. On the other hand, in order to avoid overlapping and confounding of

group and outcome variables, the construct to be used as the study outcome should

be purely subjective and not specific, but general.

Model to study Objective findings/Subjective state of health

A new theoretical base was created with this procedure. It reversed the model of

Filipp and Ferring (1991) described above in Figure 1 for differential-diagnostic

purposes in the field of somatic diseases. The modified Viennese model no longer

serves to describe components of quality of life at different levels. Rather, the

congruent or discrepant assessments of experts and patients on the basis of

functional assessments in the process of rehabilitation serve to determine different

groups whose health-related quality of life then is compared as the outcome (Figure

2).

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objective findings,

subjective patient´s evaluation of functional capacity

expert´s evalution of patient´s functional

capacity

good less good

good

the fortunate health dilemma

less good

disease paradox the unfortunate

Figure 2. Viennese “Objective findings/Subjective state of health-model” (“Befund/Krankheitserleben”-model).

Pilot study: Patients, Material, and Methods

Orthopedic patients are very suitable for the implementation and empirical testing of

the said pre-conditions, particularly because appropriate survey instruments are

either available or being used in a standardized manner in this specialty. In the

following investigation, which was conducted in cooperation with the Orthopedic

Hospital Speising in Vienna, the Harris Hip Score (Harris, 1969) was used as the

objective instrument to measure the specific functional capacity of orthopedic patients

while the Hannover Functional Questionnaire (Kohlmann & Raspe, 1996; Kohlmann

et al., 1999) was employed as the subjective instrument. The first is a classification

instrument used by orthopedists to assess the success of hip surgery. Four different

dimensions evaluate the patient’s current functional capacity as assessed by the

orthopedist: mobility, functional activity, pain and deformity. The sum of the four

weighted scores is used to assign the patient to one of four categories on a scale

from 0 to 100 (very good: 90–100, good: 80–90, moderate: 70–80 and poor: less

than 70). The questionnaire to survey subjective functional capacity contains 18

items with which the patient assesses his/her impairment of motor activities in daily

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life in a three-categorical format (“yes”, “yes but with difficulty”, “no”; a copy of the

questionnaire can be found in Knahr, Kryspin-Exner, Jagsch, Freilinger & Kasparek,

1998, page 325). Low scores indicate good functional capacity. Thus, the two

instruments to assess specific function are poled in opposite directions.

The sample consisted of patients who had received total arthroplasty for age-related

signs of wear in the hip joint. The assessments of the orthopedist and the patients

themselves in respect of the specific functional capacity, using the instruments

available for this purpose, before the operation and from the catamnestic

investigation after one year, were analyzed. The results used to compare the two

time points have been reported elsewhere (Knahr et al., 1998). The patients were

assigned to the groups at the time point of catamnesis (one year post-surgery)

because the functional evaluation here is based on the patients’ rehabilitative status.

The group classification was operationalized by respective dichotomization of the two

assessments into “good” and “not good” based on the data from the empirical

sample, so that statements like “good compared to the assessments of other

patients” or “less good compared to the assessments of other patients” were

rendered possible. From a practical point of view the procedure was implemented by

dividing the scores of patients and experts at the median value.

The investigated sample consisted of 139 patients who had been operated on in the

Orthopedic Hospital Speising in Vienna. Of this initial cohort, 101 patients (72.7%)

could be examined one year after the operation. The mean age of the patients at the

time of surgery was 64.2 years (SD, 12.7 years; range, 25 to 88 years); the

female/male ratio was 2:1 (63.4% were women). The diagnoses were mainly

idiopathic coxarthrosis and necrosis of the femoral head; the principal symptoms

were pain and limitation of mobility. Part 1 of the Nottingham Health Profile (NHP)

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was used as the instrument to measure health-related quality of life. A validated

German translation of this questionnaire has been provided by Kohlmann, Bullinger

and Kirchberger-Blumstein (1997). Part 1 consists of a total of 38 items to be

answered in a yes/no format. These 38 items are assigned to six different sub-scales:

loss of energy (EN, 3 items),

pain (PA, 8 items),

negative emotional reaction (EM, 9 items),

sleeping difficulties (SL, 5 items),

social isolation (SO, 5 items), and

limitation of physical mobility (PM, 8 items).

This instrument was selected because it is very economical (takes 5 to 10 minutes)

and possesses good test criteria (the Cronbach alpha value for the internal

consistency of the sub-scales is between 0.65 and 0.85 (Jagsch & Pils, 2006;

Kohlmann et al., 1997). For comparing baseline as well as continuous

sociodemographic and disease-specific data (age and duration of symptoms) one-

way ANOVA was used with following post-hoc Scheffé tests, Chi2-tests for

categorical data (gender). t-tests for dependent samples were used to compare

means between the time points. In case of non-normal distribution of data,

nonparametric Wilcoxon’s signed-ranks test was used. The level of significance was

set at 5%.

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Results

The data of the entire cohort show that the operation leads to a significant

enhancement of health-related quality of life. There were significant improvements in

five of the six sub-scales after one year. Only in the social sector the scores

remained constant; the baseline data already showed very good social integration

before surgery (Figure 3).

postpre

100

80

60

40

20

0

EN **

PA **

EM **

SL **

SO

PM **

37

64

56

32

52

17

26

31

77

38

50

Figure 3. Changes in health-related quality of life of the whole sample of patients (N=101).

** p<0.01

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To date, the five-year catamnesis has been performed for about 50% of the initial

cohort (about 70 patients). This assessment showed that the enhancement in health-

related quality of life can be retained over a long period of time (Knahr, Jagsch &

Kryspin-Exner (2003).

For the subsequent analysis the patients were divided into the four groups described

above, using a double median split, at the catamnesis investigation performed one

year after surgery. The empirical mean was 93 for the Harris Hip Score and 33.33 for

the Hannover functional questionnaire; the correlation between the two functional

scores was -0.54 (explained variance, 29.2%). In all, about three quarters of the

patients were able to achieve concurrence between subjective and objective

assessments; these patients consisted of nearly equal numbers of the “fortunate” (38

patients; 37.6%) and the “unfortunate” (37 patients; 36.6%). The remaining one

quarter was divided into 15 patients in the “disease paradox” (14.9%) and 11 patients

in the “health dilemma” (10.9%) (Figure 4).

unfortunate 36.6%

DP 14.9%

HD 10.9%

fortunate 37.6%

Figure 4. Distribution of the patients according to the four subgroups. HD = health dilemma, DP = disease paradox

17

Comparisons between the four groups revealed no differences concerning gender

distribution (Chi2=1.011, df=3, p=0.798) or duration of symptoms (F=1.052, df=3,

p=0.373). Differences in age yet showed a significant result in the four group ANOVA

comparison (F=2.836, df=3, p=0.042) but proved insignificant then in the following

post-hoc Scheffé tests (p>0.10). The analysis of the baseline scores at the time of

surgery revealed only marginal differences between the four random sample

fractions. The “fortunate” and the “unfortunate” differed only in the sub-scale “physical

mobility” (p=0.031; post-hoc Scheffé test). As predicted, “fortunate” patients achieved

the greatest advancements in health-related quality of life. In this group, significant

improvements (p<0.01) were registered in all dimensions except social isolation,

analogous to the total sample (Figure 5a).

postpre

100

80

60

40

20

0

EN **

PA **

EM **

SL **

SO

PM **

13

56

17

49

8

23

11

78

11

36

Figure 5a. Changes in health-related quality of life of the “fortunate” (n=38). ** p<0.01

18

Likewise, as expected, the “unfortunate” patients achieved the poorest results,

characterized by a concurrent poor evaluation of the rehabilitative functional capacity.

Improvements (p<0.01) were registered only for pain (Figure 5b).

postpre

100

80

60

40

20

0

EN

PA **

EM

SL

SO

PM

64

71

79

46

54

2927

56

79

6359

Figure 5b. Changes in health-related quality of life of the “unfortunate” ( =37). ** p<0.01

In the comparison of the groups, the patients of the “health dilemma” group also

revealed the same longitudinal pattern; improvements (p<0.01) were registered only

for pain while the other scales showed no statistical differences compared to the

baseline values (Figure 5c).

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postpre

100

80

60

40

20

0

EN

PA **

EM

SL

SO

PM

51

60

5

40

47

13

21

34

69

4548

Figure 5c. Changes in health-related quality of life of the health dilemma patients (n=11). ** p<0.01

The data of the “disease paradox” group, on the other hand, were quite similar to

those of “fortunate” patients, but on a slightly lower level: significant improvements for

pain, sleeping difficulties, physical mobility (p<0.01) and emotional reaction (p<0.05)

(Figure 5d).

20

postpre

100

80

60

40

20

0

EN

PA **

EM *

SL **

SO

PM **

22

69

78

25

56

16

31

21

73

40

62

Figure 5d. Changes in health-related quality of life of the disease paradox patients (n = 15). ** p<0.01, * p<0.05

The changes are shown in detail in Table 1.

Table 1. Significance of changes of the whole sample and of the four subsamples in the subscales of NHP whole sample fortunate HD DP unfortunate df=100 df=37 df=10 df=14 df=36 EN t=2.680, p=0.009 t=4.093, p<0.001 t=0.430, p=0.676 t=1.784, p=0.096 t=-0.597, p=0.554 PA t=12.293, p<0.001 t=14.409, p<0.001 t=4.113, p=0.002 t=6.136, p<0.001 t=3.966, p<0.001 EM t=3.073, p=0.003 t=3.284, p=0.002 t=1.099, p=0.298 t=2.355, p=0.034 t=-0.273, p=0.787 SL t=6.209, p<0.001 t=5.771, p<0.001 t=0.841, p=0.420 t=3.944, p=0.001 t=1.666, p=0.104 SO t=0.884, p=0.379 t=-0.467, p=0.644 Z=-1.732, p=0.083 Z=-0.577, p=0.564 t=0.850, p=0.401 PM t=8.573, p<0.001 t=12.005, p<0.001 t=0.886, p=0.397 t=6.219, p<0.001 t=1.697, p=0.098 Note. HD = health dilemma, DP = disease paradox; EN = loss of energy, PA = pain, EM = emotional reaction, SL = sleeping problems, SO = social isolation, PM = problems in physical mobilty

21

Discussion

In conclusion, this procedure showed that a characterization of patients in terms of

agreement versus discrepancy of functional capacity at the subjective and objective

levels yielded extremely diverse results in respect of the health-related quality of life

of these patients. Improvements only in one out of six subscales could be found for

all patients of all four groups, that is pain. In all other subscales except social

isolation a much more differentiated result can be seen where mainly the subjects’

personal estimation of their current functional capacity seems to be of much greater

importance than the objective assessment: “fortunate” patients and patients of the

“disease paradox” mainly benefit from the intervention while the other two groups

with exception of the pain section do not. These findings may help to draw

conclusions concerning differential diagnosis and the subsequent treatment of these

patients. Additional medical and/or psychological services should not be randomly

distributed among all patients according to the “watering can” principle, but rather

should be focused on the two groups that particularly are in need of such resources,

i.e. the “unfortunate” patients and patients of the “health dilemma”. The goal is to

improve health-related quality of life. Patients of the “disease paradox”, on the other

hand, appear to possess inner “health resources” to a great degree, which enable

them to grade their individual state better than the expert. As a result, their quality of

life achieves approximately the same level as that reported by “fortunate” patients.

The model of objective findings/subjective state of health presented here may help to

be used for a need-oriented application of rehabilitation services in the future bringing

together both macro- and micro-health needs (Asadi-Lari, Packham & Gray,

2003). Thus, a future plan may be to create a diversified rehabilitation program on

basis of the patient groups of the proposed model, in order to help activate such

22

potential inner “health resources” in this process and thus guarantee the best

possible health-related quality of life for all patients with different needs.

23

References

Allison, P.J., Locker, D. & Feine, J.S. (1997). Quality of life: A dynamic construct.

Social Science & Medicine, 45, 221–230.

Asadi-Lari, M., Packham, C. & Gray, D. (2003). Need for redefining needs. Health

and Quality of Life Outcomes, 1, 34.

Brickman, P., Coates, D. & Janoff-Bulman, R. (1978). Lottery winners and accident

victims: Is happiness relative? Journal of Personality and Social Psychology, 36,

917–927.

Bullinger, M. & Hasford, J. (1991). Evaluating quality-of-life measures for clinical trials

in Germany. Controlled Clinical Trials, 12, S91–S105.

Bullinger, M., Ravens-Sieberer, U. & Siegrist, J. (2000). Gesundheitsbezogene

Lebensqualität in der Medizin – eine Einführung. In M. Bullinger, J. Siegrist & U.

Ravens-Sieberer (Hrsg.), Lebensqualitätsforschung aus medizinpsychologischer

und -soziologischer Perspektive. Jahrbuch für Medizinischen Psychologie (S. 11–

21). Göttingen: Hogrefe.

Filipp, S.-H. & Ferring, D. (1991). Zur inhaltlichen Bestimmung und Erfassung von

Lebensqualität im Umfeld schwerer körperlicher Erkrankungen [On the

conceptualization and assessement of quality of life in the context of severe

physical diseases]. Praxis der Klinischen Verhaltensmedizin und Rehabilitation, 4,

274–283.

Fritz, J.M. & Piva, S.R. (2003). Physical Impairment Index: Reliability, validity, and

responsiveness in patients with acute low back pain. Spine, 28, 1189–1194.

Harris, W.H. (1969). Traumatic arthritis of the hip after dislocation and acetabular

fractures: Treatment by mold arthroplasty. An end-result study using a new

method of result evaluation. Journal of Bone and Joint Surgery (Am.), 51, 737–

755.

Jagsch, R. & Pils, K. (2006). Which instrument is more suitable to assess health-

related quality of life: Nottingham Health Profile or Short-Form 36? Wiener

Medizinische Wochenschrift, 156 (5/6), 149–157.

Knahr, K., Jagsch, R. & Kryspin-Exner, I. (2003). Long-term quality of life evaluation

of patients with total hip arthroplasty. Hip International, 13, 167–176.

Knahr, K., Kryspin-Exner, I., Jagsch, R., Freilinger, W. & Kasparek, M. (1998).

Beurteilung der Lebensqualität vor und nach Implantation einer Hüft-

Totalendoprothese [Evaluating the quality of life before and after implantation of a

24

total hip endoprothesis]. Zeitschrift für Orthopädie und ihre Grenzgebiete, 136,

321–329.

Kohlmann, T., Bullinger, M. & Kirchberger-Blumstein, I. (1997). Die deutsche Version

des Nottingham Health Profile (NHP): Übersetzungsmethodik und

psychometrische Validierung. Sozial- und Präventivmedizin, 42, 175–185.

Kohlmann, T. & Raspe, H.H. (1996). Der Funktionsfragebogen Hannover zur

alltagsnahen Diagnostik der Funktionsbeeinträchtigung durch Rückenschmerzen

(FFbH-R) [Hannover Functional Questionnaire in ambulatory diagnosis of

functional disability caused by backache]. Rehabilitation (Stuttg.), 35, I–VIII.

Kohlmann, T., Richter, T., Heinrichs, K., Peschel, U., Knahr, K. & Kryspin-Exner, I.

(1999). Entwicklung und Validierung des Funktionsfragebogens Hannover für

Patienten mit Arthrosen der Hüft- und Kniegelenke (FFbH-OA). In Verband

deutscher Rentenversicherungsträger (Hrsg.), 8.

Rehabilitationswissenschaftliches Kolloquium, Tagungsband. DRV-Schriften Bd.

12 (S. 40–42). Frankfurt am Main: VDR.

Leplege, A. & Hunt, S. (1997). The problem of quality of life in medicine. Journal of

the American Medical Association, 278, 47–50.

Lindholm, E., Brevinge, H., Bergh, C.-H., Körner, U. & Lundholm, K. (2003).

Relationships between self-reported health related quality of life and measures of

standardized exercise capacity and metabolic efficiency in amid-aged and aged

healthy population. Quality of Life Research, 12, 575–582.

Mabe, P.A., Hobson, D.P., Jones, L.R. & Jarvis, R.G. (1988). Hypochondriacal traits

in medical inpatients. General Hospital Psychiatry, 10, 236–244.

Majani, G., Giardini, A. & Scotti, A. (2005). Subjective impact of osteoarthritis flare-

ups on patient´s quality of life. Health and Quality of Life Outcomes, 3, 14.

Mellner, C. & Lundberg, U. (2003). Self- and physician-rated general health in

relation to symptoms and diseases among women. Psychology, Health &

Medicine, 8, 123–134.

Michel, A., Kohlmann, T. & Raspe, H. (1997). The association between clinical

findings on physical examination and self-reported severity in back pain. Results

of a population-based study. Spine, 22, 296–303.

Myrtek, M. (1998). Gesunde Kranke, kranke Gesunde. Bern: Huber.

25

Ormel, J., Lindenberg, S., Steverink, N. & von Korff, M. (1997). Quality of life and

social production functions: A framework for understanding health effects. Social

Science & Medicine, 45, 1051–1063.

Pilowsky, I. (1978). A general classification of abnormal illness behaviours. British

Journal of Medical Psychology, 51, 131–137.

Ravens-Sieberer, U., Cieza, A. & Bullinger, M. (2001). Lebensqualität aus

Patientensicht. Eröffnung einer neuen Perspektive für die Medizin [Quality of life

from the patient's point of view. Opening up a new perspective for medicine].

Chirurgische Praxis, 59, 3–12.

Richter, J., Schwarz, M., Eisemann, M. & Bauer, B. (2003). Quality of life as an

indicator for successful geriatric inpatient rehabilitation – A validation study of the

“Vienna List”. Archives of Gerontology and Geriatrics, 37, 265–276.

Robra, B.P., van der Heyden, E. & Machens, D. (1982). Herz-Kreislauf-

Vorsorgeprogramm VW/Salzgitter. Auswertung der Ergebnisse 1974 bis 1979.

Niedersächsisches Ärzteblatt, 21, 757–766.

Rosenberg, R. (1995). Health-related quality of life between naturalism and

hermeneutics. Social Science & Medicine, 41, 1411–1415.

Smith, K.W., Avis, N.E. & Assmann, S.F. (1999). Distinguishing between quality of

life and health status in quality of life research: A meta-analysis. Quality of Life

Research, 8, 447–459.

Tully, M.P. & Cantrill, J.A. (1999). Subjective outcome measures – A primer.

Pharmacy World and Science, 21, 101–109.

Waddell, G., Somerville, D., Henderson, I. & Newton, M. (1992). Objective clinical

evaluation of physical impairment in chronic low back pain. Spine, 17, 617–628.

WHOQoL Group (1995). World Health Organization quality of life assessment

(WHOQoL): Position paper from the World Health Organization.

Social Science & Medicine, 41, 1403–1409.