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