Muscle Strength in Type-2 Diabetes Mellitus and its Relationship with Biochemical Parameters and Microvascular Complications

Introduction: Sensory symptoms and deficits are frequently observed in diabetic polyneuropathy, but motor deficits are more difficult to recognise or often neglected. As a part of a rehabilitation team, we observed altered muscle strength in Type-2 Diabetes Mellitus (T2DM) in relation to neuropathy. Weakness in muscles in DM has significant effects on patient's daily living activities.

Aim: To find the relationship of muscle strength in diabetes subjects characterised by microvascular complications (retinopathy, nephropathy and peripheral neuropathy associated) and biochemical measurements.

Materials and Methods: The present observational study was conducted at the Department of Orthopaedics, Srinivas Institute of Medical Sciences, Mangaluru, Karnataka, India for a period of nine months from February 2020 to November 2020. Study included 72 patients divided into T2DM subjects (n=36) and non diabetic controls (n=36) with age <75 years, with a diabetic history ≥5 years. By using standard laboratory methods, biochemical measurements were taken, which included Fasting Blood Sugar (FBS) level, Glycated Haemoglobin (HbA1c), serum creatine, serum insulin, C-peptide and albumin excretion rate. The retinal status of the diabetic subjects were classified as normal, non proliferative and proliferative retinopathy, renal status classified as incipient and overt nephropathy and neuropathy as asymptomatic and symptomatic by ophthalmologist, nephrologist and neurologist respectively. Muscle strength of the upper extremities and lower extremities were measured by using hand-held dynamometer (Baseline® LiTE®).

Results: Out of total 72 subjects, the mean age of diabetic and non diabetic group was 55.69±5.50 years and 55.91±5.21 years, respectively. In diabetic subjects, the median value of serum creatine was 1.04 mg/dL , FBS was 171 mg/dL, HbA1c was 9.1%,serum insulin was 24.62 mU/L, C-peptide was 1.13 ng/mL and albumin excretion rate was 57.6 mg/24 hours. Approximately, 10.5% reduction was observed at ankle dorsiflexion and plantar flexion of both sides, 7% reduction of knee extension (both side), and right knee flexion, whereas, the left knee shows a marked 10.81% reduction in muscle strength.

Conclusion: Type-2 diabetes subjects have weakness of extensors and flexors of the upper and lower extremity (shoulder and hip strength not assessed in this study) with predominant reduction of muscle strength in the lower limbs.