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

Abstract

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 (continued)

Personalizing Evidence for Shoulder Fracture Patients Using an Extended Instrumental Variable Causal Forest Algorithm

“…1 and A.2 in the Appendix replicate the patient factor summary tables found in the prior research for this study population. 78 Table 1 provides summary statistics across the study population of the IV-CFA estimated effects of early surgery relative to conservative management for the benefit and detriment outcomes, respectively (Figures A.1 & A.2 in the Appendix show the distributions). On average, the IV-CFA estimates show early surgery increased the absolute probability of benefit and detriment outcomes by .196 and .135, respectively.…”

“…The prior study included 72,823 patients 78 and used a measure of local area surgical practice styles as an instrument (see the description below). Additional control variables were specified in this study as recommended by the literature 101 for this type of instrument including county-level life expectancy 102 and county-level adjusted per capita Medicare spending.…”

“…Data are from a prior instrumental variable (IV) study for Medicare fee-for-service patients with a new PHF in 2011 that used local area surgery rates as an instrumental variable and showed positive associations between early surgery rates and detriments (1-year mortality and morbidity rates) which varied when patients were stratified by single baseline factors. 78 It was unknown whether additional reference classes could be identified and the extent to which early surgery rates were associated with both benefit and detriment within each reference 2 class. IV-CFA is initially used here to estimate early surgery effects for both detriment and benefit outcomes for each patient in the study population.…”

Personalizing Evidence for Shoulder Fracture Patients Using an Extended Instrumental Variable Causal Forest Algorithm

“…We used data for Medicare fee-for-service patients with a new proximal humerus fracture (PHF) in 2011. 78 It is thought that 15-30% of elderly PHF patients are good candidates for early surgery. [90][91][92][93] Traditionally, elderly patient with fractures which are not displaced are not candidates for early surgery.…”

“…Data are from a prior instrumental variable (IV) study for Medicare fee-for-service patients with a new PHF in 2011 that used local area surgery rates as an instrumental variable and showed positive associations between early surgery rates and detriments (1-year mortality and morbidity rates) which varied when patients were stratified by single baseline factors. 78 It was unknown whether additional reference classes could be identified and the extent to which early surgery rates were associated with both benefit and detriment within each reference class. IV-CFA is initially used here to estimate early surgery effects for both detriment and benefit outcomes for each patient in the study population.…”