Skip to main content
. Author manuscript; available in PMC: 2021 Apr 6.
Published in final edited form as: Sci Transl Med. 2020 Sep 23;12(562):eaba4487. doi: 10.1126/scitranslmed.aba4487

Table 5.

Negative binomial regressions of PrEP uptake onto clients’ socio-demographic characteristics1

Covariate-unadjusted2 Covariate-adjusted3
RR (95% CI) P4 RR (95% CI) P5
Female 0.85 (0.69 – 1.04) 0.175 0.90 (0.72 – 1.13) 0.398
Age group
 16–25 years Ref. Ref.
 26–35 years 1.29 (1.01 – 1.67) 0.083 1.27 (1.01 – 1.59) 0.088
 36–45 years 1.65 (1.29 – 2.12) 0.010 1.51 (1.20 – 1.89) 0.011
 >45 years 1.48 (1.18 – 1.87) 0.031 1.37 (1.11 – 1.69) 0.032
Education
 No formal schooling Ref. Ref.
 Some or completed primary school 0.88 (0.62 – 1.25) 0.582 0.98 (0.73 – 1.30) 0.804
 Some or completed secondary school 0.70 (0.51 – 0.97) 0.039 0.83 (0.61 – 1.12) 0.255
 Some or completed tertiary education 0.80 (0.50 – 1.29) 0.432 0.92 (0.60 – 1.41) 0.741
Relationship status
 Multiple partners Ref. Ref.
 One partner, living together 0.78 (0.61 – 1.00) 0.099 0.77 (0.58 – 1.03) 0.195
 One partner, not living together 0.66 (0.52 – 0.83) 0.062 0.73 (0.55 – 0.95) 0.148
 Single, no relationship 0.53 (0.27 – 1.02) 0.079 0.57 (0.25 – 1.31) 0.198
Member of a priority population 1.61 (1.07 – 2.41) 0.018 1.19 (1.00 – 1.40) 0.177

PrEP = HIV pre-exposure prophylaxis; RR=relative risk; CI=confidence interval

1

All regressions were negative binomial regression models with a binary variable (‘fixed effect’) for each healthcare facility. The outcome was a binary variable indicating whether the participant took up PrEP. The sample was restricted to those 1,543 participants who were considered at risk of acquiring HIV. P-values were computed using the score bootstrap procedure with Webb weights and 1,000 replications.(42)

2

These regressions only had one independent variable.

3

These regressions had all variables shown in the table as independent variables, i.e., ten-year age group (categorical), education (categorical), relationship status (categorical), and whether the participant was in at least one priority population (binary).

4

The p-values for the chi-square test testing the null hypothesis that all categories of the categorical variables are equal to zero was 0.0001 for age group, 0.0085 for education, and 0.0018 for relationship status.

5

The p-values for the chi-square test testing the null hypothesis that all categories of the categorical variables are equal to zero was 0.0026 for age group, 0.1237 for education, and 0.1320 for relationship status.