Hand dysfunction in type 2 diabetes mellitus: Systematic review with meta-analysis

Background: People with type 2 diabetes mellitus frequently show complications in feet and hands. However, the literature has mostly focused on foot complications. The disease can affect the strength and dexterity of the hands, thereby reducing function. Objectives: This systematic review and meta-analysis focused on identifying the existing evidence on how type 2 diabetes mellitus affects hand strength, dexterity and function. Methods: We searched MEDLINE via PubMed, CINHAL, Scopus and Web of Science, and the Cochrane central register of controlled trials for reports of studies of grip and pinch strength as well as hand dexterity and function evaluated by questionnaires comparing patients with type 2 diabetes mellitus and healthy controls that were published between 1990 and 2017. Data are reported as standardized mean difference (SMD) or mean difference (MD) and 95% confidence intervals (CIs). Results: Among 2077 records retrieved, only 7 full-text articles were available for meta-analysis. For both the dominant and non-dominant hand, type 2 diabetes mellitus negatively affected grip strength (SMD: -1.03; 95% CI: -2.24 to 0.18 and -1.37, -3.07 to 0.33) and pinch strength (-1.09, -2.56 to 0.38 and -1.12, -2.73 to 0.49), although not significantly. Dexterity of the dominant hand did not differ between diabetes and control groups but was poorer for the non-dominant hand, although not significantly. Hand function was worse for diabetes than control groups in 2 studies (MD: -8.7; 95% CI: -16.88 to -1.52 and 4.69, 2.03 to 7.35). Conclusion: This systematic review with meta-analysis suggested reduced hand function, specifically grip and pinch strength, for people with type 2 diabetes mellitus versus healthy controls. However, the sample size for all studies was low. Hence, we need studies with adequate sample size and randomized controlled trials to provide statistically significant results.