Evidence-based program planning for incidence reduction and prevention
Raleigh, State Capital
Harnett County
Fort Bragg, Military Base
Objectives
• Identify monthly or seasonal patterns of disease
• Identify target population for greatest impact
Introduction
• Staffing levels in the STD clinic remain constant while the burden of disease increases
• Public health benefits from outreach and prevention education
Public Health Significance
• Chlamydia and gonorrhea rates rose 6% from 2011 to 2012
• The population of Harnett County is rising 3% per year
• STD prevention education for a community of individuals
Study Sample
• NCEDSS: Passive Surveillance
• n = 2255 over 57 months
• Case Definition: Laboratory Positive Chlamydia Trachomatis and Neisseria Gonorrhea
Event Distribution by Age
Variables
Dependent: Event Rate
Independent: 1. Month / Season2. Age Group
- High School (13 to 18)- College (19 to 22)- Adult (≥ 23)
Method
• Cross-Sectional = Single observation
• Analysis of Variance
• Tukey Honestly Significant Difference
Age Group Sum of
Squares
df Mean
Square
F p-value
All 1792.809 11 162.983 1.173 0.332
Within groups 6250.700 45 138.904
13 to 18 232.190 11 21.108 1.224 0.299
Within groups 775.950 45 17.243
19 to 22 833.146 11 75.741 3.243 0.003
Within groups 1051.100 45 23.358
≥ 23 218.211 11 19.837 0.711 0.722
Within groups 1256.350 45 27.919
ANOVA by Month
Mean
Difference
Std.
Error Sig.
95% Confidence Interval
Lower Upper
MAR JAN 14.250 3.417 0.007 2.480 26.020
FEB 13.250 3.417 0.016 1.480 25.020
APR 9.400 3.242 0.176 -1.770 20.570
MAY 11.400 3.242 0.042 0.230 22.570
JUN 13.400 3.242 0.008 2.230 24.570
JUL 12.600 3.242 0.015 1.430 23.770
AUG 14.400 3.242 0.003 3.230 25.570
SEP 10.800 3.242 0.066 -0.370 21.970
OCT 14.800 3.242 0.002 3.630 25.970
NOV 7.800 3.242 0.423 -3.370 18.970
DEC 14.600 3.242 0.002 3.430 25.770
Tukey HSD
Age Group Sum of
Squares
df Mean
Square
F p-value
All 791.969 3 263.990 1.929 0.136
Within groups 7251.540 53 136.822
13 to 18 52.466 3 17.489 0.970 0.414
Within groups 955.674 53 18.032
19 to 22 378.427 3 126.142 4.440 0.007
Within groups 1505.818 53 28.412
≥ 23 105.050 3 35.017 1.355 0.267
Within groups 1369.512 53 25.840
ANOVA by Season
Mean
Difference
Std.
Error Sig.
95% Confidence Interval
Lower Upper
Spring Summer 6.038 1.981 0.018 0.78 11.29
Fall 3.705 1.981 0.253 -1.55 8.96
Winter 6.648 2.053 0.011 1.20 12.09
Summer Spring -6.038 1.981 0.018 -11.29 -0.78
Fall -2.333 1.946 0.630 -7.50 2.83
Winter 0.610 2.020 0.990 -4.75 5.97
Fall Spring -3.705 1.981 0.253 -8.96 1.55
Summer 2.333 1.946 0.630 -2.83 7.50
Winter 2.944 2.020 0.470 -2.41 8.30
Winter Spring -6.648 2.053 0.011 -12.09 -1.20
Summer -0.610 2.020 0.990 -5.97 4.75
Fall -2.944 2.020 0.470 -8.30 2.41
Tukey HSD
Mean and IQR : College Age Group
Discussion
Strengths: • Statistical Significance of findings• Data Set
Weaknesses: • Under-reporting in passive surveillance• Procedural under-reporting of males• Data for negative test results not included• Data represent date of testing, not infection**
Discussion / Conclusions
• It is not unreasonable to tailor a prevention and education program to college age residents in late winter to early spring
• Spring break: Increased rate of infection or testing?
• If infection: Pre-empt with education and condoms!
• If testing: Alternative hours of operation
• Follow-up study already in motion
QUESTIONS
ADDITIONAL REFERENCES
North Carolina Department of Health and Human Services. (2014, March). 2012 HIV/STD Surveillance Report Addendum. Retrieved from N.C. Department of Health and Human Services: Epidemiology: http://epi.publichealth.nc.gov/cd/stds/figures/std12rpt_addendum.pdf
United States Department of Commerce. (2014, December 4). Harnett County, North Carolina.Retrieved from United States Census Bureau: http://quickfacts.census.gov/qfd/states/37/37085.html