Para além da glicemia: investigando a saúde do ombro na diabetes mellitus e as manifestações da neuropatia periférica diabética nos membros superiores

Abstract

Introduction: People with diabetes mellitus (DM) seem to have a higher prevalence of shoulder pain compared with the general population. Diabetic peripheral neuropathy (DPN), one of the most prevalent chronic complications of DM, is systemic and progressive; however, its investigation has predominantly focused on the lower limbs (LL). The contribution of DM and DPN to shoulder-related pain and functional outcomes remains unclear. Moreover, the manifestation of DPN in the upper limbs (UL) and its relationship with DPN severity in the LL are poorly explored. Within this context, this doctoral thesis comprises three studies: Study 1: Objective: To investigate the association between the presence of DM and shoulder pain, motion, strength, and functional performance. Methods: Cross-sectional study including 75 individuals with DM and 37 controls. Outcomes assessed were shoulder pain and disability (SPADI), range of motion (RoM), isometric strength, and shoulder functional performance (TFAST). Multiple linear regression models were fitted considering DM as the main independent variable and age, body mass index (BMI), and physical exercise level as covariates. Results and conclusion: DM was associated with reduced active (β = −10.98°; p < 0.05) and passive (β = −8.10°; p < 0.05) internal rotation RoM and poorer shoulder functional performance (β = −12.78 repetitions; p < 0.05). No associations were observed for the remaining outcomes. These findings suggest that DM is related to specific impairments in shoulder mobility and functional performance, reinforcing the importance of early and targeted monitoring to identify and manage shoulder alterations in this population. Study 2: Objective: To compare shoulder pain, motion, strength, and functional performance among individuals with DM with and without DPN and controls without DM, and to investigate the association between DPN severity and shoulder-related outcomes in individuals with DM. Methods: Cross-sectional study with 112 participants allocated into three groups: DM with DPN (n = 38), DM without DPN (n = 37), and controls (n = 37). The presence and severity of DPN in the LL, shoulder pain and disability (SPADI), RoM, muscle strength, and functional performance (TFAST) were assessed. Analyses included between-group comparisons and multiple linear regression models adjusted for age, BMI, and physical exercise level. Results and conclusion: Individuals with DM and DPN exhibited higher levels of shoulder pain and disability, reduced shoulder active internal rotation RoM, reduced shoulder strength, and poorer shoulder functional performance compared with individuals with DM without DPN and controls (p < 0.05). In adjusted analyses, DPN severity was not independently associated with most shoulder outcomes, except for serratus anterior strength (β = 0.692 N/kg; p < 0.05), suggesting that clinical and behavioral factors such as age, dietary habits, and physical exercise may influence this relationship. Study 3: Objective: To characterize the manifestation of DPN in the UL and compare these outcomes between individuals with DM with and without DPN in the LL, as well as to examine the association between LL DPN severity and outcomes suggestive of DPN manifestation in the UL. Methods: Cross-sectional study including 76 individuals with DM, divided into two groups: with DPN in the LL (n = 38) and without DPN in the LL (n = 38). UL-DPN manifestation was assessed through self-reported neuropathic symptoms and physical examination of tactile and vibratory sensitivity, maximum handgrip strength, and hand dexterity (Jebsen–Taylor Test). Group comparisons and association analyses were performed using appropriate statistical tests. Results and conclusion: Individuals with DPN in the LL presented a higher frequency of neuropathic symptoms in the UL, worse tactile and vibratory hand sensitivity, reduced handgrip strength, and poorer hand dexterity compared with individuals without DPN in the LL (p < 0.05). LL-DPN severity correlated with the number of neuropathic symptoms in the UL, tactile and vibratory sensory impairment of the hand, reduced handgrip strength, and poorer hand dexterity (p < 0.05). These findings reinforce the systemic and progressive nature of DPN and highlight the importance of including UL assessment in clinical screening protocols for individuals with DM.