Characteristics and Patterns of Retention in Hypertension Care in Primary Care Settings From the Hypertension Treatment in Nigeria Program

Abstract

Background: More than 1.2 billion adults worldwide have hypertension. High retention in clinical care is essential for long-term management of hypertension, but 1-year retention rates are less than 50% in many resource-limited settings.

Objective: To evaluate short-term retention rates and associated factors among patients with hypertension in primary health care centers in the Federal Capital Territory of Nigeria.

Design, setting, and participants: In this cohort study, data were collected by trained study staff from adults aged 18 years or older at 60 public, primary health care centers in Nigeria between January 2020 and July 2021 as part of the Hypertension Treatment in Nigeria (HTN) Program. Patients with hypertension were registered.

Exposures: Follow-up visit for hypertension care within 37 days of the registration visit.

Main outcomes and measures: The main outcome was the 3-month rolling average 37-day retention rate in hypertension care, calculated by dividing the number of patients who had a follow-up visit within 37 days of their first (ie, registration) visit in the program by the total number of registered patients with hypertension during multiple consecutive 3-month periods. Interrupted time series analyses evaluated trends in retention rates before and after the intervention phase of the HTN Program. Mixed-effects, multivariable regression models evaluated associations between patient-, site-, and area council-level factors, hypertension treatment and control status, and 37-day retention rate.

Results: In total, 10 686 patients (68.3% female; mean [SD] age, 48.8 [12.7] years) were included in the analysis. During the study period, the 3-month rolling average 37-day retention rate was 41% (95% CI, 37%-46%), with wide variability among sites. The retention rate was higher among patients who were older (adjusted odds ratio [aOR], 1.01 per year; 95% CI, 1.01-1.02 per year), were female (aOR, 1.11; 95% CI, 1.01-1.23), had a higher body mass index (aOR, 1.01; 95% CI, 1.00-1.02), were in the Kuje vs the Abaji area council (aOR, 2.25; 95% CI, 1.25-4.04), received hypertension treatment at the registration visit (aOR, 1.27; 95% CI, 1.07-1.50), and were registered during the postintervention period (aOR, 1.16; 95% CI, 1.06-1.26).

Conclusions and relevance: The findings suggest that retention in hypertension care is suboptimal in primary health care centers in Nigeria, although large variability among sites was found. Potentially modifiable and nonmodifiable factors associated with retention were identified and may inform multilevel, contextualized implementation strategies to improve retention.

Conflict of interest statement

Conflict of Interest Disclosures: Dr G. Shedul reported receiving grants from the National Institutes of Health (NIH) during the conduct of the study. Dr Ugwuneji reported receiving nonfinancial support from Resolve to Save Lives during the conduct of the study. Dr Nwankwo reported receiving grants from the NIH during the conduct of the study. Dr Hirschhorn reported receiving grants from the National Heart, Lung, and Blood Institute (NHLBI), NIH during the conduct of the study. Dr G.L. Shedul reported receiving grants from the NIH during the conduct of the study. Dr Kandula reported receiving grants from the NHLBI, NIH during the conduct of the study. Dr Huffman reported having patents planned for combination therapy for the treatment of heart failure, patents pending for heart failure polypills, and a secondary appointment at the George Institute for Global Health, whose social enterprise business, George Health Enterprises Pty Ltd and its subsidiary, George Medicines Pty Ltd, have received investment funds to develop blood pressure–lowering drugs. No other disclosures were reported.

Figures

Figure 1.. Three-Month Rolling Average 37-Day Retention Rate Between the Registration Visit and First Follow-up Visit for Patients With Hypertension in Primary Health Care Centers in the Federal Capital Territory of Nigeria

Inner horizontal lines of the boxes indicate medians; outer horizontal lines of the boxes, interquartile ranges; and whiskers, 95% CIs. The FCT numbers are the study identification numbers for each of the primary health care centers.

Figure 2.. Interrupted Time Series With Level Change Regression Model Adjusted for Seasonality

Monthly point estimates are based on the observed retention rate, determined from the date of the first (ie, registration) clinic visit. Circles indicate the mean 37-day retention rate in each month; whiskers, 95% CIs; solid line, predicted 37-day retention rate trend based on the seasonally adjusted regression model; dotted line, predicted 37-day retention rate trend without intervention; dashed line, deseasonalized trend; and shaded area, implementation phase.