Observational stepped-wedge analysis of a community health worker-led intervention for diabetes and hypertension in rural Mexico

Abstract

Objectives: There is emerging interest and data supporting the effectiveness of community health workers (CHWs) in non-communicable diseases (NCDs) in low/middle-income countries (LMICs). This study aimed to determine whether a CHW-led intervention targeting diabetes and hypertension could improve markers of clinical disease control in rural Mexico.

Design and setting: A prospective observational stepped-wedge study was conducted across seven communities in rural Chiapas, Mexico from March 2014 to April 2018.

Participants: 149 adults with hypertension and/or diabetes.

Intervention: This study was conducted in the context of the programmatic roll-out of an accompaniment-based CHW-led intervention designed to complement comprehensive primary care for adults with diabetes and/or hypertension. Implementation occurred sequentially at 3-month intervals with point-of-care data collected at baseline and every 3 months thereafter for 12 months following roll-out in all communities.

Outcome measures: Primary outcomes were glycated haemoglobin (HbA1c) and systolic blood pressure (SBP), overall and stratified by baseline disease control. We conducted an individual-level analysis using mixed effects regression, adjusting for time, cohort and clustering at the individual and community levels.

Results: Among patients with diabetes, the CHW-led intervention was associated with a decrease in HbA1c of 0.35%; however, CIs were wide (95% CI -0.90% to 0.20%). In patients with hypertension, there was a 4.7 mm Hg decrease in SBP (95% CI -8.9 to -0.6). In diabetic patients with HbA1c ≥9%, HbA1c decreased by 0.96% (95% CI -1.69% to -0.23%), and in patients with uncontrolled hypertension, SBP decreased by 10.2 mm Hg (95% CI -17.7 to -2.8).

Conclusions: We found that a CHW-led intervention resulted in clinically meaningful improvement in disease markers for patients with diabetes and hypertension, most apparent among patients with hypertension and patients with uncontrolled disease at baseline. These findings suggest that CHWs can play a valuable role in supporting NCD management in LMICs.

Trial registration number: NCT02549495.

Keywords: CHW; LMIC; NCD; cardiovascular disease; community health worker; diabetes; hypertension; non-communicable disease; stepped-wedge.

Figure 1

Stepped-wedge schematic for the study. Programmatic roll-out was randomised by community (cluster) with sequential implementation of the intervention resulting in each community contributing time as unexposed (purple) and exposed (peach) to the CHW-led intervention. Data were collected at the start of each 3-month time point across two cohorts regardless of whether the intervention had been implemented. In the first cohort (communities 1–4), data collection took place from March 2014 through January 2016. In the second cohort (communities 5–7), data collection took place from July 2016 through April 2018. Delays in baseline data collection in cohort 1 shortened the duration of period 1 from 3 months to 1 month. Organisational delay in roll-out for cohort 2 shortened the baseline pre-randomisation phase and resulted in a 3-month delay in implementation in community 7.

Figure 2

Flow of participants through the study.

Figure 3

Diabetes and hypertension continuous outcomes. Adjusted mean difference between exposed and unexposed for glycated haemoglobin (HbA1c) among patients with diabetes (A) and average systolic blood pressure in patients with hypertension (B). Individual-level mixed effects analysis adjusting for time and cohort with clustering by individual and community presented as estimate (square) and 95% CIs (lines). A. Diabetes outcomes among all patients (n=73 (543 time points)) and dichotomised between poorly controlled (HbA1c ≥9%, n=37 (278)) and not poorly controlled (HbA1c <9%, n=32 (247)) at baseline. B. Hypertension outcomes among all patients (n=117 (869 time points)) and dichotomised between not controlled (n=49 (364)) and controlled (blood pressure (in mm Hg) <140/90, <130/80 if concomitant diabetes, <150/90 if age ≥80 according to 2010/2014 Mexican Ministry of Health guidelines, n=62 (486)) at baseline. Four patients with diabetes and seven patients with hypertension not included in stratified analysis due to missing baseline control data.