The Relationship Between Multimorbidity and Glycemic Control in Older Adults with Type 2 Diabetes in Family Medicine Settings: A Systematic Review and Meta-Analysis

Abstract

Background: In patients with type 2 diabetes mellitus (T2DM), glycemic control is a major predictor of long-term results. The existence of multimorbidity—defined as the concurrent presence of several chronic illnesses—can, nevertheless, make diabetes management difficult and affect glycemic outcomes. Notwithstanding growing interest, the association between multimorbidity and glycemic control continues to be reported inconsistently across groups and care situations.

Methodology: Using PRISMA criteria, relevant studies published up to 2025 were found via structured database searches and screened to assess the link between multimorbidity and glycemic control in adults with T2DM. A systematic review and meta-analysis were carried out. The qualitative synthesis encompassed nine research. Key variables included study design, population demographics, glycemic control definitions and multimorbidity, and reported relationships between comorbid disorders and glycemic outcomes.

Results: The included studies varied in geographic location, sample size (ranging from 87 to 969,531 participants), and research design. Most investigations focused on seniors (60 years). Though some research showed a link between multimorbidity and subpar glycemic control, others showed neutral or paradoxical results—with some comorbid profiles linked to better outcomes maybe as a result of more aggressive therapy. Meta-analysis showed neither obesity nor hypertension significantly correlated with poor glycemic control (IV: 1.17; 95% CI: 0.881.56; P = 0.279; I = 87.4%). Moreover, patients with more than two co-morbidities had not much higher risk of bad glycemic control (RR: 1.12; 95% CI: 0.991.28; P = 0.078).

Conclusion:In T2DM, multimorbidity and glycemic control have a complicated and context-dependent relationship. Although some comorbidities including obesity and CKD may have detrimental effects on glycemic control, the total number of comorbid conditions is not always a predictor of bad control.