Association of Surgical Treatment With Adverse Events and Mortality Among Medicare Beneficiaries With Proximal Humerus Fracture

IMPORTANCE: Meta-analyses of randomized clinical trials suggest that the advantages and risks of surgery compared with conservative management as the initial treatment for proximal humerus fracture (PHF) vary, or are heterogeneous across patients. Substantial geographic variation in surgery rates for PHF suggests that the optimal rate of surgery across the population of patients with PHF is unknown. OBJECTIVE: To use geographic variation in treatment rates to assess the outcomes associated with higher rates of surgery for patients with PHF. DESIGN, SETTING, AND PARTICIPANTS: This comparative effectiveness research study analyzed all fee-for-service Medicare beneficiaries with proximal humerus fracture in 2011 who were continuously enrolled in Medicare Parts A and B for the 365-day period before and immediately after their index fracture. Data analysis was performed January through June 2019. EXPOSURE: Undergoing 1 of the commonly used surgical procedures in the 60 days after an index fracture diagnosis. MAIN OUTCOMES AND MEASURES: Risk-adjusted area surgery ratios were created for each hospital referral region as a measure of local area practice styles. Instrumental variable approaches were used to assess the association between higher surgery rates and adverse events, mortality risk, and cost at 1 year from Medicare’s perspective for patients with PHF in 2011. Instrumental variable models were stratified by age, comorbidities, and frailty. Instrumental variable estimates were compared with estimates from risk-adjusted regression models. RESULTS: The final cohort included 72 823 patients (mean [SD] age, 80.0 [7.9] years; 13 958 [19.2%] men). The proportion of patients treated surgically ranged from 1.8% to 33.3% across hospital referral regions in the United States. Compared with conservatively managed patients, surgical patients were younger (mean [SD] age, 80.4 [8.1] years vs 78.0 [7.2] years; P < .001) and healthier (Charlson Comorbidity Index score of 0, 14 863 [24.4%] patients vs 3468 [29.1%] patients; Function-Related Indicator score of 0, 20 720 [34.0%] patients vs 4980 [41.8%] patients; P < .001 for both), and a larger proportion were women (49 030 [80.5%] patients vs 9835 [82.5%] patients; P < .001). Instrumental variable analysis showed that higher rates of surgery were associated with increased total costs ($8913) during the treatment period, increased adverse event rates (a 1–percentage point increase in the surgery rate was associated with a 0.19–percentage point increase in the 1-year adverse event rate; β = 0.19; 95% CI, 0.09-0.27; P < .001), and increased mortality risk (a 1–percentage point increase in the surgery rate was associated with a 0.09–percentage point increase in the 1-year mortality rate; β = 0.09; 95% CI, 0.04-0.15; P < .01). Instrumental variable mortality results were even more striking for older patients and those with higher comorbidity burdens and greater frailty. Risk-adjusted estimates suggested that surgical patients had higher costs (increase of $17 278) and more adverse events (a 1–percentage point increase in the surgery rate was associated with a 0.12–percentage point increase in the 1-year adverse event rate; β = 0.12; 95% CI, 0.11 to 0.13; P < .001) but lower risk of mortality after PHF (a 1–percentage point increase in the surgery rate was associated with a 0.01–percentage point decrease in the 1-year mortality rate; β = −0.01; 95% CI, −0.015 to −0.005; P < .001). CONCLUSIONS AND RELEVANCE: This study found that higher rates of surgery for treatment of patients with PHF were associated with increased costs, adverse event rates, and risk of mortality. Orthopedic surgeons should be aware of the harms of extending the use of surgery to more clinically vulnerable patient subgroups.