Sustainability of a 12-month lifestyle intervention delivered by community health workers in reducing blood pressure in Nepal: 5-year follow-up of the COBIN open-label, cluster randomised trial
Rajshree Thapa, Ayse Zengin, Dinesh Neupane, Shiva Raj Mishra, Sweta Koirala, Per Kallestrup, Amanda G Thrift
Lancet Global Health · 2023 · DOI: 10.1016/S2214-109X(23)00214-0
Countries: Nepal
What Was Studied
This is a 5-year (60-month) follow-up of the COBIN cluster-randomised trial, which tested whether a 12-month lifestyle-counselling and blood-pressure-monitoring intervention delivered by 43 female community health volunteers (FCHVs) to 1638 adults (aged 25-65) across 14 wards in Lekhnath Municipality, Kaski, Gandaki Province could sustainably lower blood pressure after the active intervention ended. In the original 12-month trial, FCHVs in seven intervention clusters visited households three times a year to counsel on salt, alcohol, smoking, physical activity, and stress, and to measure blood pressure; seven usual-care clusters received only routine government services. This paper reports the pre-specified primary outcome -- change in systolic blood pressure from baseline to 60 months -- using an intention-to-treat analysis of 1352 of the original 1468 twelve-month completers (92.1% retention), followed up between October 2020 and May 2022, four years after the intervention had ceased.
What They Found
Contrary to the original trial's short-term benefit (systolic blood pressure was 2.3-4.9 mmHg lower in the intervention arm at 12 months), the benefit was not sustained at 5 years and appears to have reversed. Mean systolic blood pressure rose from 121.6 mmHg at baseline to 132.9 mmHg at 60 months in the former intervention group (an increase of 10.4 mmHg, 95% CI 9.1-11.6), compared with a rise from 122.4 to 129.2 mmHg (6.0 mmHg, 95% CI 4.6-7.5) in the usual-care group -- an adjusted between-group difference of 4.1 mmHg (95% CI 2.2-5.8) unfavourable to the former intervention group. The reversal was also seen in those hypertensive at baseline (adjusted difference 4.9 mmHg, 95% CI 0.8-9.1, worse in the intervention group) and in diastolic blood pressure (2.1 mmHg, 95% CI 0.9-3.4, worse in intervention). Overall hypertension prevalence in the cohort rose from 29.2% (395/1352) at baseline to 46.0% (622/1352) at 60 months, and a larger share of previously normotensive intervention participants developed hypertension (23%, 92/396) than usual-care participants (16%, 43/277).
What This Means for Nepal
COBIN's FCHVs are the same ~50,396-strong volunteer cadre (DoHS Annual Health Report 2080/81) that MoHP/DoHS now plans to lean on for WHO PEN-based NCD service expansion at primary care level -- precisely the kind of scale-up this trial's sobering result should inform. Three actions follow: (1) DoHS's WHO PEN and NCD-scale-up planning should build in indefinite (not time-limited) FCHV contact for hypertensive and at-risk patients, since this trial shows a 12-month burst of counselling does not just fade but can leave patients worse off than no intervention once monitoring stops; (2) given the already-documented risk of an ageing FCHV cadre with inconsistent compensation (DoHS AHR 2080/81), any NCD task shifted onto FCHVs needs a costed continuity plan -- the earlier retrospective cost-effectiveness analysis of COBIN's 12-month phase found it cost-effective, but this 5-year result means those estimates should be revisited assuming ongoing, not one-off, delivery; (3) NHRC- and MoHP-approved trials of CHW-led NCD interventions should be required to include at least 24-month post-intervention follow-up before informing national policy, since this is the first Nepal-based evidence that short lifestyle interventions can produce rebound harm -- a pattern invisible in typical 12-month evaluations.
Contextualisation
Nepal's NCD burden is large and rising -- hypertension affects 24.5% of adults (STEPS 2019) and NCDs account for 66-71% of all deaths (WHO 2022; Nepal Burden of Disease 2019) -- and the government's current reform priority is expanding WHO PEN-based NCD services at primary care using the same ~50,396-strong FCHV cadre this trial deployed. COBIN is a Nepal-based cluster RCT that directly tested the FCHV-delivered lifestyle-counselling model MoHP/DoHS are now trying to scale, and its finding that benefits reverse once FCHVs' active monitoring stops is a first-order caution for any FCHV-based NCD scale-up plan, not a generic 'intervention effectiveness' result.