Effectiveness of Diabetes Self-management Education Intervention Elements: A Meta-analysis

CANADIAN JOURNAL OF DIABETES. 2009;33(1):18-26.

18 | CANADIAN JOURNAL OF DIABETES

ABSTRACTOBJECTIvES: This meta-analysis aimed to examine differenc-es in knowledge, self-management behaviours and metabol-ic control associated with various diabetes self-management education (DSME) intervention elements.

M E T h O D S : Fifty randomized, controlled trials evaluating DSME interventions in adults with type 2 diabetes, pub-lished in English between 1990 and 2006, were included in the analysis. Data related to type of intervention, teaching method, mode of delivery and dose were extracted.

RESULTS: Overall, the weighted mean effect size of the DSME interventions was 1.29 for knowledge, 0.51 for metabolic control and 0.36 for self-management behaviours. Differences in outcomes were observed for number of sessions, duration of intervention and provision of booster sessions.

C O N C L U S I O N S : These results provide researchers and practitioners with evidence to guide the design of DSME interventions that are effective in improving knowledge, behaviour and metabolic control outcomes among patients with type 2 diabetes.

KEywORDS: diabetes, intervention, intervention elements, meta-analysis, randomized controlled trial, self-manage-ment education.

RÉSUMÉOBJECTIFS : Cette méta-analyse visait à examiner les différences quant aux connaissances, aux comportements d’autogestion et au contrôle métabolique associées à diverses interventions en matière d’éducation sur l’autogestion du diabète.

M É T h O D E S : L’analyse a porté sur cinquante essais contrôlés avec répartition aléatoire sur l’éducation sur l’autogestion du diabète menés auprès d’adultes atteints de diabète de type 2 et dont les résultats ont été publiés en anglais entre 1990 et 2006. Les données sur le type d’intervention, la méthode d’enseignement, le mode de prestation et la dose ont été extraites.

RÉSULTATS : Globalement, l’ampleur moyenne pondérée de l’effet des interventions en matière d’éducation sur l’autogestion du diabète a été de 1,29 pour les connaissances, de 0,51 pour le contrôle métabolique et de 0,36 pour les com-portements d’autogestion. Le nombre de séances, la durée de l’intervention et la prestation de séances de rappel ont produit des différences pour ce qui est des résultats obtenus.

C O N C L U S I O N S : Ces résultats donnent aux chercheurs et aux praticiens des données qui les aideront à élaborer des interventions en matière d’éducation sur l’autogestion du diabète qui amélioreront les connaissances, les comporte-ments et le contrôle métabolique chez les patients atteints de diabète de type 2.

M O T S C L É S : diabète, éducation sur l’autogestion, inter-vention, essai contrôlé avec répartition aléatoire, méta-analyse, interventions

OBJECTIvES The prevalence of type 2 diabetes is increasing worldwide. This type of diabetes, if not well controlled, is associated with a range of complications (retinopathy, nephropathy, neuropathy, coronary heart disease and cerebrovascular dis-ease), leading to significant morbidity and mortality (1-3).

Lifeng Fan1 MScN RN, Souraya Sidani2 PhD RN

1Faculty of Nursing, University of Toronto, Toronto, Ontario, Canada2School of Nursing, Ryerson University, Toronto, Ontario, Canada

Address for correspondence:

Lifeng Fan, 42 Neddie Drive, Toronto, Ontario, Canada M1T 2T1

Telephone: (416) 335-1213, E-mail: [email protected]

ORIgINAL RESEARCh

Effectiveness of Diabetes Self-management Education Intervention Elements: A Meta-analysis


DiAbeTeS SeLF-MANAgeMeNT eDUCATiON MeTA-ANALySiS | 19

Unhealthy behaviours, including physical inactivity, high cal-orie and fat intake, inadequate monitoring of blood glucose and poor adherence to medications, are all well-established risk factors for the development of complications (4,5). In addition to pharmacological treatments to reduce hyperglyce-mia, hypercholesterolemia and hypertension, lifestyle changes leading to increased levels of physical activity and a healthier diet have been found to substantially alter the course of type 2 diabetes and decrease the risk of diabetes-related complica-tions (6). Diabetes self-management education (DSME) is the process of teaching patients about the application of self-care strategies to optimize their metabolic control, prevent com-plications and improve their quality of life (7).

DSME is now recognized as a valuable resource that can help patients participate actively in their own diabetes management (8,9), and has been included in a number of treatment guidelines for diabetes (10,11). Several studies have evaluated the effectiveness of DSME interventions in improving patients’ knowledge of diabetes/treatment, self-management behaviours and metabolic control (12,17). However, although the results of these studies demonstrated the effectiveness of DSME interventions in improving self-management, they did not evaluate which parts of the inter-vention (e.g. type, teaching method, mode of delivery, dose) were associated with the intended outcomes (18,19).

Understanding which intervention elements — given in what way and at what level — are most effective is criti-cal for guiding practice. Such information can help direct the design and implementation of DSME interventions to ensure that they are effective in assisting people with dia-betes successfully manage their condition. Further, most of the meta-analyses have focused on the effects of DSME interventions on metabolic outcomes (e.g. blood glucose level) to the exclusion of behavioural outcomes (e.g. self-care knowledge and behaviours), yet improvement with respect to behavioural outcomes reflects the lifestyle change required to achieve metabolic control and, hence, to prevent the complications of diabetes.

The objectives of this meta-analysis were 1) to describe the DSME interventions in terms of the following elements: type, teaching method, mode of delivery and dose; and 2) to examine differences between intervention elements with respect to the outcomes of knowledge, self-management behaviours and metabolic control. The ultimate goal was to provide researchers and practitioners with evidence to bet-ter guide the design of DSME interventions.

METhODSOverviewRandomized, controlled trials (RCTs) that evaluated the effects of DSME on self-care knowledge, self-management behaviours and metabolic control were reviewed. The RCT

design is considered the gold standard for determining the impact of interventions on intended outcomes, because it minimizes the potential of selection bias. Baseline differ-ences between the experimental and comparison groups could confound the effects of the intervention (20); there-fore, operational definitions of the variables of interest — elements and outcomes of DSME interventions — were prespecified to clarify the selection criteria and facilitate data extraction. Effect sizes were computed for each outcome and compared across all elements of DSME interventions to determine the effect of each intervention element on the outcomes.

The operational definitions of intervention elements were derived from the work of Sidani and Braden (18) and Blue and Black (19), and from the theoretical and empirical liter-ature relevant to DSME interventions. DSME interventions were categorized into 4 types: 1) educational, which refers to interventions in which patients with diabetes primarily receive information from healthcare providers, focusing on the provision of information to improve patients’ knowl-edge of diabetes self-management; 2) behavioural, which refers to interventions targeting improved self-management behaviours, with a focus on active skills training and emphasizing change in skills and/or lifestyle associated with the implementation of a diabetes self-management regimen, such as diet, physical activity, blood glucose monitoring or foot care; 3) psychological, which refers to interventions in which the primary goal is to address negative mood states, addressing coping skills such as relaxation exercises, social support, etc.; and 4) mixed, encompassing a combination of the 3 types above.

Teaching methods used to provide DSME were divided into the following groups: 1) didactic, which involved con-veying diabetes-related information to patients (e.g. distri-bution of written materials, watching a video or attending formal individual or group sessions) and often characterized by limited discussion or interaction between provider and participant; 2) interactive, which consisted primarily of active participant involvement in the learning process (e.g. group discussion sessions designed to train participants in skills such as problem solving or individualized goal-setting negotiation); and 3) mixed, integrating both didactic and interactive techniques.

The mode of DSME delivery was subdivided by strat-egy and format. Specific strategies used to convey content include written material available in brochure/pamphlet or online; video; communication with the healthcare provider either face-to-face or via telephone; or a combination of the above strategies. Format indicated the number of partici-pants receiving the DSME in a given session: one-on-one, group or mixed.

The dose of DSME intervention was described in


was extracted from each article: first author’s last name and year of publication; country in which the study was con-ducted; number of participants allocated to the experimen-tal and comparison groups; characteristics of the sample in terms of age (mean age), gender (percentage of women and men), education (mean number of years of formal education) and duration of diabetes (mean number of years participants had diabetes); and setting in which the DSME intervention was delivered (in-hospital, outpatient clinic, community clinic and participants’ home).

Data on the intervention elements were coded according to: 1) type of DSME intervention (educational, behavioural, psychological, mixed); 2) teaching method (didactic, inter-active, mixed); 3) strategies for delivering DSME (written material, online/web-based, video, face-to-face, phone con-tact, mixed; and 4) format (one-on-one/individual, group, mixed). The number of diabetes-related topics covered dur-ing the intervention was also coded (1 topic only and more than 1 topic). Finally, the dose of DSME was indicated by number of sessions; length of sessions (i.e. total of contact time in hours); duration of intervention delivery (in weeks); and delivery of booster sessions (yes or no).

Outcome data related to measures of central tendency (mean) and dispersion (standard deviation) for the experi-mental and comparison groups, value of the test and associ-ated p value comparing the experimental and comparison groups were reported at each occasion of measurement after implementation of the intervention. Outcomes were knowledge (total score on a knowledge questionnaire); self-management behaviours (diet, exercise, self-monitoring of blood glucose, taking medications as prescribed, preventive behaviours such as foot care and total score on measure-ments of behaviour); and metabolic control (A1C, FBG, sys-tolic and diastolic blood pressure, cholesterol, triglycerides and body weight).

Data analysisComprehensive Meta-Analysis (version 2.0) (Biostat Inc., Englewood, NJ) was used to estimate the effect size and standard error for each outcome indicator examined in each study. The most appropriate formula was applied to com-pute the effect size, based on the information reported in the article. When the experimental and comparison groups’ mean and standard deviation were related to the effect size, this represented the standardized mean difference. When these measures of central tendency and dispersion were not avail-able, values of the t- or F-test (or p value) for group compari-sons were reported; the formula proposed by Hedges (23) and Borenstein (24) was used to transform these values into effect sizes. Weighted mean effect sizes (weighted by the inverse of the variance) were computed for each outcome across stud-ies and in relation to each indicator of intervention elements.

terms of number of sessions; total contact hours; duration of the intervention; and delivery of booster sessions (additional session[s]/ telephone contact following completion of the intervention).

Selection criteriaStudies were included in the meta-analysis if they met the following selection criteria: 1) subjects were adults >18 years of age with type 2 diabetes; 2) interventions under investigation involved educational, behavioural, psychologi-cal or multiple components, delivered in acute (in-hospital) or primary (clinic, participants’ home, etc.) care settings; 3) outcomes assessed related to diabetes knowledge, self-management behaviours and metabolic control, represented by glycated hemoglobin (A1C), fasting blood glucose (FBG), blood pressure, cholesterol, triglycerides and weight/body mass index (BMI); 4) study was an RCT; and 5) the study report was published in English between January 1990 and December 2006.

Search strategiesFour electronic databases were used to search for relevant studies: National Library of Medicine (MEDLINE); Nursing and Allied Health database (CINAHL); Health STAR; and EMBASE. The following search terms were used for MEDLINE and adapted for the other databases: type 2 dia-betes mellitus/non-insulin-dependent diabetes mellitus, patient education/diabetes education and diabetes self-management education intervention, including all subheadings. Because electronic databases are incomplete (21,22), journals expected to publish on the research topic (Diabetes Care, The Diabetes Educator and Diabetic Medicine) were also searched manually. The electronic and manual searches yielded 180 articles. After reviewing the abstract and relevant sections of each article, 107 were excluded because of redundancy and/or not meeting the selection criteria. Of the 73 studies that were selected, 17 did not provide the data needed to compute effect size and 6 lacked detailed information on the intervention elements. As a result, a total of 50 studies comprised the sample for this meta-analysis.

Data extractionData from eligible studies were extracted (LF) and results were reviewed (SS). Data were extracted relating to study characteristics, intervention elements and outcomes of interest to this meta-analysis. Guided by the operational definitions presented earlier, a coding scheme was devel-oped to extract relevant data from each article. The coding scheme allowed numeric values to be assigned to the catego-ries reflecting the variables. Data pertaining to each variable were obtained from relevant sections of each article.

The following information about study characteristics



The Z-value was examined to determine whether the weighted mean effect size was significantly different from zero.

RESULTSStudy characteristicsThere were 50 studies included in this meta-analysis. Half (50%) were published between 2001 and 2006, 24% were published between 1996 and 2000, and 26% were published between 1990 and 1995. About 56% were conducted in North America (Unites States and Canada), 34% in Europe (United Kingdom, Italy, Finland, Germany and Netherlands), 10% in Asia (Korea and Taiwan) and 4% in Australia. Sample size varied from as low as 29 to as high as 1139, with the fol-lowing distribution: ≤50 participants (10% of studies), 51 to 100 participants (40%), 101 to 200 (19%) and ≥201 (31%). The age of participants ranged from 32 to 67 years, with a mean of 56.4 (±6.2) years across all studies. Gender distribu-tion was reported in 48 studies: female participants accounted for ≤40% of the sample in 5 studies, 41 to 60% in 28 studies and ≥61% in 15 studies. The mean number of formal years of education was indicated in 20 studies, varying from 3 to 15 years, with an average of 9.7 years (±3.5) across all studies. Only 33 studies reported on the participants’ duration of dia-betes; in 76% of studies, mean duration of diabetes was less than 10 years, with a mean of 7.9 years (±3.5) across stud-ies. DSME interventions were delivered in hospital settings (2 studies), outpatient clinics (34 studies), community clinics (11 studies) and in the participants’ home (3 studies).

intervention elementsData on DSME intervention elements are presented in Table 1. Typically, DSME interventions were characterized as mixed, encompassing different combinations of educa-tional, behavioural and psychological types. They were offered using a mix of didactic and interactive teaching methods, through face-to-face communication with the provider in a mix of one-on-one and group formats. In general, DSME interventions covered more than 1 topic related to diabetes self-management. Interventions were delivered over several sessions, with a mean of 10 (range 1 to 28), for a mean of 17 contact hours (range 1 to 52) over a mean of 22 weeks (range 1 to 48). Forty-three interventions (68%) did not give booster sessions.

Outcomes of DSMeThe weighted mean effect sizes (ES) for each outcome of interest, averaged across studies that reported relevant val-ues, were significantly different from zero (Table 2). The largest effect size was observed for knowledge (ES=1.29). The effect size for 5 of 7 indicators of metabolic control and for 3 of the 6 self-management behaviours were of a moderate magnitude (0.40–0.73); effect sizes for overall

Table 1. DSME intervention elements (N=50 studies)

Elements Number of studies (%)

Type of intervention

Educational 2 (4)

Behavioural 9 (18)

Psychological 2 (4)

Mixed 37 (54)

Teaching method

Didactic 10 (20)

Interactive 10 (20)

Mixed 30 (60)

Strategies

Written material 0 (0)

Online/web-based 2 (4)

Video 1 (2)

Face-to-face 30 (60)

Phone contact 2 (4)

Mixed 15 (30)

Format

One-on-one 16 (32)

Group 20 (40)

Mixed 14 (28)

Number of diabetes-related topics

Focus on 1 topic 9 (18)

Mixed 41 (82)

Number of sessions*

≤5 14 (31)

6–10 17 (38)

>10 14 (31)

Total contact hours†

≤10 15 (46)

11–20 7 (21)

>20 11 (33)

Duration‡

≤8 weeks 11 (26)

9–24 weeks 15 (37)

>24 weeks 15 (37)

Delivery of booster session

Yes 16 (32)

No 34 (68)

*n=45; mean 10±7 (1–28); †n=33; mean 17±13 (1–52)‡n=41; mean 22±17 (1–48) DSME = diabetes self-management education


knowledge (ES=1.32) and a moderate effect for metabolic control (ES=0.50). Educational components had a moderate effect on knowledge (ES=0.59).

Teaching methodLarger effect sizes were found for mixed teaching methods with respect to knowledge (ES=1.69) and metabolic control (ES=0.69). In contrast, the effect size for self-care behaviour was the largest for interactive teaching methods (ES=0.54).

Delivery strategiesNo consistent pattern was evident across outcome variables based on strategies used to deliver education. However, strategies involving interactions with healthcare providers (either face-to-face or by phone) produced larger effect sizes than other strategies. Phone contact appeared to have a pattern across both self-management behaviour and meta-bolic control. Mixed strategies were not more effective than individual strategies.

metabolic control (ES=0.51) were larger than those for overall self-management behaviours (ES=0.36). The overall weighted mean of effect size across studies was of moderate magnitude (ES=0.56).

Differences in outcomes in relation to DSMeintervention elementsThe weighted mean effect sizes for each of the various outcomes — knowledge, self-management behaviours and metabolic control — observed in relation to the elements of the DSME interventions, are presented in Table 3.

Components of interventionsLarger effect sizes were found for behavioural types of DSME interventions than for other types with respect to self-care behaviours (ES=0.92) and metabolic outcomes (ES=0.63). Psychological types of interventions had moderate effects on self-care behaviours (ES=0.67) and metabolic control (ES=0.40). Mixed interventions yielded a larger effect for

Table 2. weighted mean effect sizes (d) for each outcome, averaged across studies

Variables Studies, n d SE Range p value

Knowledge 19 1.29 0.19 0.90–1.67 0.00

Self-management behaviours

Diet 18 0.26 0.04 0.18–0.35 0.00

Exercise 16 0.40 0.09 0.29–0.57 0.00

SMBG 9 0.70 0.18 0.34–1.05 0.00

Medication 10 0.29 0.09 0.11–0.46 0.00

Recognition of complications 9 0.73 0.18 0.37–1.09 0.00

Foot care 6 0.34 0.09 0.03–0.38 0.02

Overall self-management behaviours 68 0.36 0.03 0.30–0.43 0.00

Metabolic outcomes

GHB 41 0.71 0.12 0.50–0.92 0.00

FBG 15 0.56 0.17 0.29–0.89 0.00

Systolic blood pressure 12 0.57 0.14 0.30–0.83 0.00

Diastolic blood pressure 10 0.66 0.20 0.27–1.05 0.00

Cholesterol 20 0.52 0.13 0.26–0.78 0.00

Triglycerides 15 0.25 0.08 0.10–0.41 0.00

Body weight/BMI 34 0.28 0.08 0.12–0.43 0.00

Overall metabolic outcomes 163 0.51 0.05 0.42–0.60 0.00

Overall weighted mean effect sizes 271 0.56 0.03 0.50–0.62 0.00

BMI = body mass indexFBG = fasting blood glucoseGHB = gamma-hydroxybutyrateSMBG = self-monitoring of blood glucose



Table 3. weighted mean effect sizes (d) in relation to intervention elements

Intervention elementsKnowledge Self-management

behaviourMetabolic control

d±SE p value d±SE p value d±SE p value

Type of intervention

Educational 0.59±0.36 >0.05 — — — —

Behavioural — — 0.92±0.24 ≤0.05 0.63±0.24 ≤0.05

Psychological — — 0.67±0.32 ≤0.05 0.40±0.25 >0.05

Mixed 1.32±0.20 ≤0.05 0.33±0.03 ≤0.05 0.50±0.05 ≤0.05

Teaching method

Didactic 0.56±0.14 ≤0.05 0.47±1.33 ≤0.05 0.16±0.05 ≤0.05

Interactive — — 0.54±0.11 ≤0.05 0.42±0.07 ≤0.05

Mixed 1.69±0.32 ≤0.05 0.29±0.03 ≤0.05 0.69±0.06 ≤0.05

Strategies

Online/web-based — — 0.16±0.04 ≤0.05 0.56±0.21 ≤0.05

Video 0.59±0.36 ≤0.05 — — — —

Face-to-face 1.44±0.24 ≤0.05 0.39±0.04 ≤0.05 0.57±0.06 ≤0.05

Phone contact — — 0.95±0.34 ≤0.05 0.63±1.25 >0.05

Mixed 0.64±0.07 ≤0.05 0.29±0.05 ≤0.05 0.30±0.05 ≤0.05

Format

One-on-one 2.04±075 ≤0.05 0.50±0.08 ≤0.05 0.63±0.12 ≤0.05

Group 0.60±0.09 ≤0.05 0.35±0.05 ≤0.05 0.28±0.05 ≤0.05

Mixed 2.99±0.98 ≤0.05 0.34±0.07 ≤0.05 0.73±0.08 ≤0.05

Number of diabetes-related topics

Focus on 1 topic — — 0.47±0.21 ≤0.05 0.51±0.08 ≤0.05

Mixed 1.29±0.19 ≤0.05 0.33±0.03 ≤0.05 0.52±0.05 ≤0.05

Number of sessions

≤5 0.57±0.07 ≤0.05 0.54±0.12 ≤0.05 0.39±0.20 >0.05

6–10 0.88±0.20 ≤0.05 0.35±0.05 ≤0.05 0.74±0.18 ≤0.05

>10 2.52±0.54 ≤0.05 0.29±0.06 ≤0.05 0.83±0.16 ≤0.05

Total contact hours

≤10 0.71±0.11 ≤0.05 0.58±0.11 ≤0.05 0.44±0.11 ≤0.05

11–20 3.45±3.18 >0.05 0.39±0.13 ≤0.05 1.07±0.21 ≤0.05

>20 1.22±0.46 ≤0.05 0.23±0.12 >0.05 0.71±0.10 ≤0.05

Duration

≤8 weeks 0.63±0.06 ≤0.05 0.32±0.09 ≤0.05 0.10±0.03 ≤0.05

9–24 weeks 053±0.26 ≤0.05 0.22±0.06 ≤0.05 0.44±0.09 ≤0.05

>24 weeks 2.59±0.71 ≤0.05 0.38±0.07 ≤0.05 0.66±0.07 ≤0.05

Delivery of booster session

Yes 2.62±0.64 ≤0.05 0.30±0.05 ≤0.05 0.61±0.07 ≤0.05

No 0.48±0.09 ≤0.05 0.36±0.04 ≤0.05 0.42±0.06 ≤0.05


behaviours and metabolic control in adult patients with type 2 diabetes. The overall weighted mean effect size was +0.56, which signals moderate but significant improvements for all outcomes. The effect size was greatest for knowledge gain, followed by metabolic control outcomes and self-management behaviours. The effect sizes obtained in this study are slightly larger than those reported in previous meta-analyses, which included studies conducted prior to 1990, used a variety of study designs and involved patients with both type 1 or type 2 diabetes (12-14).

The types of DSME intervention have changed in recent years. Mixed educational and behavioural or psychological types accounted for 54% of interventions in this analysis and were found to be most effective in increasing knowl-edge and achieving metabolic control. This is consistent with previous studies, which found that education com-bined with specific behavioural change strategies produced the greatest benefits (28,29).

Education techniques have also evolved since earlier meta-analyses were conducted (13,14); teaching methods have shifted from didactic presentations to mixed didactic and patient–provider interactive programs that facilitate patients’ active involvement. The mixed teaching method was used in 60% of studies included in this meta-analysis, and it was more effective than either didactic or interactive teaching methods alone in improving knowledge, meta-bolic control and self-management behaviour. Mixed DSME interventions generally included group sessions covering basic knowledge and problem-solving skills, combined with individual sessions with an educator; this format appeared to be effective for increasing knowledge and improving metabolic control outcomes.

Face-to-face interventions were most effective for enhanc-ing knowledge and metabolic control, while mixed delivery strategies generated a moderate effect size for knowledge. Phone contact appeared to be an effective method for deliver-ing DSME and supporting patients, particularly with respect to improving self-management behaviour and metabolic control. Phone contact is convenient, simple and less costly; it may also be useful in reaching those who have barriers to accessing DSME. Further research is needed to examine the effectiveness of phone contact as an element of DSME.

The dose of DSME intervention appeared to be sig-nificantly associated with the effects on the 3 outcomes. In general, interventions with more sessions and a longer duration yielded greater effect sizes for knowledge and metabolic control. Other studies have also shown that inter-ventions with a longer duration have been shown to yield larger effects than shorter ones (14,30-32). However, while more sessions and total contact hours appeared to be more effective with respect to knowledge and metabolic control, this was not the case for self-management behaviours. The

FormatLarger effect sizes were found for mixed formats with respect to knowledge (ES=2.99) and metabolic control outcomes (ES=0.73). For self-care behaviours, one-on-one education produced a larger effect than the other 2 formats (ES=0.50).

Number of diabetes-related topicsEducational interventions that covered multiple or mixed topics yielded consistently larger effect sizes for knowledge and metabolic control outcomes than those addressing 1 topic. Focus on 1 topic had a greater effect size for self-management behaviours.

Number of sessionsThe general trend was to increased effect sizes for knowl-edge and metabolic control outcomes, with an increase in the number of sessions offered.

Total contact hours or length of sessionLarger effect sizes with respect to knowledge and metabolic control outcomes were observed with an increase in the total contact hours. However, fewer contact hours (≤5) gen-erated a large effect size (ES=0.58) for self-care behaviour.

DurationInterventions with a long duration (≥24 weeks) produced larger effects for all 3 outcomes.

Delivery of booster sessionLarger effects with respect to knowledge and metabolic control outcomes were found for the interventions includ-ing booster sessions.

DISCUSSION DSME has long been considered an important resource for helping patients with diabetes participate actively in their own self-management, and is even included in treatment guidelines (8-11). Examining the effectiveness of the vari-ous DSME components can help in the design, development and planning of future DSME interventions. Recent reviews and meta-analyses have found that intervention studies are generally of mixed quality, with inadequately described interventions (25-27); it has been proposed that meta- analyses with quality ratings for included studies can facili-tate the process of answering questions about DSME (26).

This meta-analysis attempted preliminarily to evaluate the effectiveness of the various components of DSME inter-ventions (including type of intervention, teaching method, teaching strategies, format, dose of intervention and delivery of booster sessions) in 50 RCTs. The results indicate that DSME interventions may improve knowledge, self-care



reason for this is unknown, but it may be true that different strategies/intervention types may be necessary to tackle each of the different domains of self-management.

Incorporating booster sessions also enhanced the effec-tiveness of DSME interventions in helping patients maintain the desired changes. Behaviour change and improvements in self-management are not self-sustaining; initial benefits may fade by the time of follow-up (25). In addition, the lifelong and progressive nature of diabetes mean that effective self-management interventions must provide ongoing follow-up and support (33). Further research is needed to address how interventions should be extended to provide lifelong support (25,26,33).

CONCLUSIONS These preliminary results provide researchers and practi-tioners with evidence to better guide the design of DSME interventions by demonstrating which elements are most effective in influencing knowledge, behaviour and metabolic control outcomes among patients with type 2 diabetes. Type of intervention (mixed, combining educational, behavioural or psychological components), teaching method (mixed didactic and interactive), mode of delivery (face-to-face and/or by phone), format (mixed one-on-one and group) and dose (more sessions and total contact hours) have all been shown to play a role in the effectiveness of DSME and should be the focus of further research efforts.

ACKNOwLEDgMENTSCanadian Diabetes Association/Diabetes Educator Section Graduate Scholarship Awards; Great-West Life, London Life & Canada Life.

AUThOR DISCLOSURES No duality of interest declared.

AUThOR CONTRIBUTIONLF designed and conducted the meta-analysis and prepared the manuscript. SS developed the coding plan for data extraction and reviewed the manuscript.

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Effectiveness of Diabetes Self-management Education Intervention Elements: A Meta-analysis