IMPACT OF RAMADAN FASTING ON CARDIOMETABOLIC RISK FACTORS IN PATIENTS WITH TYPE 2 DIABETES AND HYPERTENSION: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract

Background:

Ramadan diurnal intermittent fasting is observed by over one billion Muslims every year. Despite medical exemptions, some patients with type 2 diabetes mellitus (T2DM) and hypertension choose to fast. The cardiometabolic effects of Ramadan fasting in these high-risk populations remain clinically important and inconsistently reported.

Objectives:

To systematically assess the impact of Ramadan fasting on cardiometabolic risk markers in adults with T2DM and hypertension with quantitative synthesis of change in glycemic control, blood pressure and renal-related indices.

Methods:

A systematic review and meta-analysis was performed by following the principles of PRISMA. Seven original quantitative studies (n = 2024) were included. Continuous outcomes were combined by a random-effects model (DerSimonian-Laird). Within person-mean change (follow-up minus baseline) was pooled. When change-score standard deviations were unavailable, they were calculated using paired baseline and follow up standard deviations assuming a correlation coefficient (r=0.50). Where necessary, standard deviations were derived from reported 95% confidence intervals. The comparison from the measure which was the most Ramadan-relevant (during vs pre-Ramadan when available: otherwise post vs pre-Ramadan) was used for pooling.

Results:

Five studies provided data for HbA1c (n = 1844). Ramadan fasting was linked to statistically significant reduction in HbA1c (pooled mean change -0.78%, 95% CI -1.52 to -0.03), with substantial heterogeneity (I²=99.38%).

Three studies provided blood pressure data (n = 1426). Systolic blood pressure was reduced significantly (pooled mean change, -6.54 mmHg, 95% confidence interval -8.85 to -4.22; I² = 81.77%). Diastolic blood pressure showed non-significant pooled reduction (pooled mean change -3.22mmHg, 95%confidence interval (CI) -7.83 to 1.40; I²= 98.04%).

Renal-related outcomes were reported in two studies but were not included in a pooled analysis because of outcome non-uniformity (serum creatinine vs creatinine clearance). Individual study estimates did not show clinically significant short-term renal deterioration.

Conclusion:

In adults with T2DM and hypertension, Ramadan fasting was linked to significant though small drops in HbA1c and systolic blood pressure (no statistical difference in diastolic blood pressure). High heterogeneity implies variations in patient characteristics, medication modifications, and dietary patterns. Clinical supervision that is structured is crucial for patients who want to fast.