This study analyzed administrative claims by a US population with commercial or Medicare supplemental insurance to compare demographics, comorbid medical conditions, and health care utilization and costs among patients undergoing total hip arthroplasty (THA) with and without muscle atrophy/weakness (MAW). Patients were classified into three cohorts: having MAW during the 12 months previous to THA (pre-MAW); having MAW during or over the 12 months after THA (post-MAW); or no MAW claim (no-MAW). In total, 19,607 Medicare and 23,127 commercially insured patients were examined. Controlling for cross-cohort differences, both pre-MAW and post-MAW commercial cohorts had significantly higher total costs ($6,697 and $8,594, in USD respectively) and higher risk of all-cause hospitalization (odds ratios, 1.66 and 1.57, respectively) than the no-MAW cohort (all P < 0.05) during the 1-year follow-up. Similar trends were observed in the Medicare population.