Claims-based Identification Methods and the Cost of Fall-related Injuries Among US Older Adults

Abstract

Objectives: Compare expenditures of fall-related injuries (FRIs) using several methods to identify FRIs in administrative claims data.

Research design: Using 2007-2009 Medicare claims and 2008 Health and Retirement Survey data, FRIs were identified using external-cause-of-injury (e-codes 880/881/882/884/885/888) only, e-codes plus a broad set of primary diagnosis codes, and a newer approach using e-codes and diagnostic and procedural codes. Linear regression models adjusted for sociodemographic, health, and geographic characteristics were used to estimate per-FRI, service component, patient cost share, expenditures by type of initial FRI treatment (inpatient, emergency department only, outpatient), and total annual FRI-related Medicare expenditures.

Subjects: The analysis included 5497 community-dwelling adults ≥65 (228 FRI, 5269 non-FRI individuals) with continuous Medicare coverage and alive during the 24-month study.

Results: The 3 FRI identification methods produced differing distributions of index FRI type and varying estimated expenditures: $12,171 [95% confidence interval (CI), $4662-$19,680], $5648 (95% CI, $3819-$7476), and $9388 (95% CI, $5969-$12,808). In all models, most spending occurred in hospital, outpatient, and skilled nursing facility (SNF) settings, but greater proportions of SNF and outpatient spending were observed with commonly used FRI identification methods. Patient cost-sharing was estimated at $691-$1900 across the 3 methods. Inpatient-treated index FRIs were more expensive than emergency department and outpatient-treated FRIs across all methods, but were substantially higher when identifying FRI using only e-codes. Estimated total FRI-related Medicare expenditures were highly variable across methods.

Conclusions: FRIs are costly, with implications for Medicare and its beneficiaries. However, expenditure estimates vary considerably based on the method used to identify FRIs.

Figure 1. Adjusted Annual Medicare Expenditures by Service Category for Older Adults Experiencing a Fall-related Injury (FRI) Using Three Methods to Identify FRIs in Medicare Claims Data, 2007-9

Note: The expenditure outcome is expenditures in the post period minus expenditures in the pre period (“expenditures change score”) and the predictor of interest is an indicator for whether the observation is from the FRI vs. non-FRI cohort. The estimated marginal effect of this indicator, or the beta coefficient, therefore reflects the differential change in expenditures experienced over time between individuals who did and did not have an FRI. Because this methodology controls for measurable and unmeasurable confounders that do not vary within an individual over time, the difference in change scores can be interpreted as the incremental expenditures associated with an FRI during the year after falling. The models control for baseline sociodemographic, health, and geographic characteristics. Method 1 involves the use of e-codes (880, 881, 882, 884, 885, or 888) only. Method 2 uses the same e-codes plus primary inpatient diagnostic codes indicating fractures, dislocations, sprains, strains, head injuries, and contusions (ICD-9 diagnostic codes 800-848, 850-854, and 920-924). Method 3 involves FRIs identified using the adapted UCLA/RAND algorithm15 in which FRIs are identified using inpatient (hospital and SNF) ICD-9 primary diagnoses and the same e-codes plus outpatient diagnoses and procedural codes. Models were estimated using OLS regression with robust standard errors. The respective analytic sample sizes for models estimated separated using FRI identification Methods 1-3 were 5,518, 5,479, and 5,497. The models do not include individuals who died during the post-index period. Separate models were estimated for each payment source. The percentage of total estimated expenditures across the three methods for hospital, outpatient, skilled nursing facility, home health, durable medical equipment, and hospice were: 35%, 11%, 48%, 8%, 0%, 0% (Method 1); 42%, 27%, 22%, 8%, 1%, 0% (Method 2); and 31%, 18%, 39%, 12%, 1%, 0% (Method 3).