Myopathy in Patients Taking Atorvastatin: A Pilot Study.

AIM: This study aims to investigate the prevalence and risk factors of statin-induced myopathy.

SUBJECTS AND METHODS: A total of 200 patients aged ≥ 40 years and taking atorvastatin 10 mg/day or more for at least 2 weeks were recruited in the study. A detailed history of participants and anthropometry of study participants was recorded, and features of myopathy were explained. Biochemical investigations along with thyroid stimulating hormone (TSH) and Vitamin D were done in all patients.

RESULTS: Mean age of study population was 54.81 ± 9.10 years. Sixty-five percent (65.5%) of atorvastatin users had coronary heart disease, 62.5% were hypertensive, 38% had diabetes. Thirty-five percent (35.5%) patients were taking 10 mg/day atorvastatin, 45% were taking 20 mg/day, and 19.5% were taking 40 mg/day. The overall frequency of myopathy among statin users was 7.5% which was significantly higher with increasing dose of atorvastatin (1.4% in 10 mg/day group, 10% in 20 mg/day group, and 12.8% in 40 mg/day, P < 0.05). The frequency of atorvastatin-related myopathy was higher in females 8.65% compared to 6.25% in males. Serum TSH levels in patients with myopathy were 4.05 ± 7.76 μIU/ml while in those without myopathy were 3.13 ± 2.88 μIU/ml ( P = 0.649). Serum 25-hydroxy Vitamin D levels were measured in 66 patients randomly. Mean levels in patients with myopathy were 15.98 ± 12.94 ng/ml and without myopathy were 10.20 ± 5.64 ng/ml ( P = 0.285).

CONCLUSION: The present study demonstrates that a significantly higher number of patients taking atorvastatin develop myopathy in real life clinical condition. The frequency of myopathy increases with increase in atorvastatin dose.