PURPOSE Peer support intervention trials have shown varying effects on glycemic control. We aimed to estimate the effect of peer support interventions delivered by people affected by diabetes (those with the disease or a caregiver) on hemoglobin A 1c (HbA 1c ) levels in adults.
METHODSWe searched multiple databases from 1960 to November 2015, including Ovid MEDLINE, the Cochrane Central Register of Controlled Trials, CINAHL, and Scopus. We included randomized controlled trials (RCTs) of adults with diabetes receiving peer support interventions compared with otherwise similar care. Seventeen of 205 retrieved studies were eligible for inclusion. Quality was assessed with the Cochrane risk of bias tool. We calculated the standardized mean difference (SMD) of change in HbA 1c level from baseline between groups using a random effects model. Subgroup analyses were predefined.RESULTS Seventeen studies (3 cluster RCTs, 14 RCTs) with 4,715 participants showed an improvement in pooled HbA 1c level with an SMD of 0.121 (95% CI, 0.026-0.217; P = .01; I 2 = 60.66%) in the peer support intervention group compared with the control group; this difference translated to an improvement in HbA 1c level of 0.24% (95% CI, 0.05%-0.43%). Peer support interventions showed an HbA 1c improvement of 0.48% (95% CI, 0.25%-0.70%; P <.001; I 2 = 17.12%) in the subset of studies with predominantly Hispanic participants and 0.53% (95% CI, 0.32%-0.73%; P <.001; I 2 = 9.24%) in the subset of studies with predominantly minority participants; both were clinically relevant. In sensitivity analysis excluding cluster RCTs, the overall effect size changed little.
CONCLUSIONSPeer support interventions for diabetes overall achieved a statistically significant but minor improvement in HbA 1c levels. These interventions may, however, be particularly effective in improving glycemic control for people from minority groups, especially those of Hispanic ethnicity. Ann Fam Med 2016;14:540-551. doi: 10.1370/afm.1982.
INTRODUCTIONT he global burden of diabetes is expected to increase from 381.8 million people affected in 2013 to an estimated 591.9 million by 2035.1 Despite increasing evidence of benefits from self-management education, only 5% of Medicare-insured and 7% of privately insured people with diabetes receive this intervention within 1 year of diagnosis. [2][3][4] Diabetes self-management education improves hemoglobin A 1c (HbA 1c ) levels, and longer duration of education further lowers levels; however, the benefits decline 1 to 3 months after education ends. 5 The World Health Organization (WHO) has stated that peer support appears to be a promising approach to improving and sustaining diabetes self-management behaviors. 6 Randomized controlled trials (RCTs) using peer support interventions delivered by people affected by diabetes have shown varying results on glycemic control, however. A 2012 narrative review examined the effect of peer support interventions on diabetes outcomes, but several additional studies with these interventions have b...