Administrative health data: guilty until proven innocent. Response to comments by Levy and Sobolev

Identification of Fall-Related Injuries in Nursing Home Residents Using Administrative Claims Data

BACKGROUND

Fall-related injuries (FRIs) are a leading cause of morbidity, mortality, and costs among nursing home (NH) residents. Carefully defining FRIs in administrative data is essential for improving injury-reduction efforts. We developed a series of novel claims-based algorithms for identifying FRIs in long-stay NH residents.

METHODS

This is a retrospective cohort of residents of NH residing there for at least 100 days who were continuously enrolled in Medicare Parts A and B in 2016. FRIs were identified using 4 claims-based case-qualifying (CQ) definitions (Inpatient [CQ1], Outpatient and Provider with Procedure [CQ2], Outpatient and Provider with Fall [CQ3], or Inpatient or Outpatient and Provider with Fall [CQ4]). Correlation was calculated using phi correlation coefficients.

RESULTS

Of 153 220 residents (mean [SD] age 81.2 [12.1], 68.0% female), we identified 10 104 with at least one FRI according to one or more CQ definition. Among 2 950 residents with hip fractures, 1 852 (62.8%) were identified by all algorithms. Algorithm CQ4 (n = 326-2 775) identified more FRIs across all injuries while CQ1 identified less (n = 21-2 320). CQ2 identified more intracranial bleeds (1 028 vs 448) than CQ1. For nonfracture categories, few FRIs were identified using CQ1 (n = 20-488). Of the 2 320 residents with hip fractures identified by CQ1, 2 145 (92.5%) had external cause of injury codes. All algorithms were strongly correlated, with phi coefficients ranging from 0.82 to 0.99.

CONCLUSIONS

Claims-based algorithms applied to outpatient and provider claims identify more nonfracture FRIs. When identifying risk factors, stakeholders should select the algorithm(s) suitable for the FRI and study purpose.

Validation of the FRAiL model to predict non-vertebral and hip fractures in nursing home residents

OBJECTIVE

Tools were unavailable to assess fracture risk in nursing homes (NH); therefore, we developed the Fracture Risk Assessment in Long term care (FRAiL) model. The objective of this validation study was to assess the performance of the FRAiL model to predict 2-year risk of non-vertebral and hip fractures in a separate large cohort of NH residents.

METHODS

This retrospective cohort study included most long-stay NH residents in the United States (N = 896,840). Hip and non-vertebral fractures were identified using Medicare claims. The Minimum Data Set (MDS) was used to identify characteristics from the original FRAiL model. Multivariable competing risk regression was used to model risk of fracture.

RESULTS

Mean age was 83.8 years (±8.2 years) and 70.7% were women. Over a mean follow-up of 1.52 years (SD 0.65), 41,531 residents (4.6%) were hospitalized with non-vertebral fracture (n = 30,356 hip fractures). In the fully adjusted model, 14/15 model characteristics remained significant predictors of non-vertebral fracture. Female sex (HR = 1.55, 95% CI 1.52, 1.59), wandering (HR = 1.30, 95% CI 1.26, 1.34), and falls (HR = 1.28, 95% CI 1.26, 1.31) were strongly associated with non-vertebral fracture rate. Total dependence in ADLs (versus independence) was associated with a decrease in non-vertebral fracture rate (HR = 0.57, 95% CI 0.52, 0.64). Discrimination was moderate in men (C-index = 0.68 for hip, 0.66 for non-vertebral) and women (C-index = 0.68 for hip, 0.65 for non-vertebral), and calibration was excellent.

CONCLUSIONS

Our model comprised entirely from routinely collected data was able to identify NH residents at greatest risk for non-vertebral fracture.

Incidence of Lower-Extremity Fractures in US Nursing Homes

BACKGROUND/OBJECTIVES

Limited studies suggest lower-extremity (LE) fractures are morbid events for nursing home (NH) residents. Our objective was to conduct a nationwide study comparing the incidence and resident characteristics associated with hip (proximal femur) vs nonhip LE (femoral shaft and tibia-fibula) fractures in the NH.

DESIGN

Retrospective cohort study.

SETTING

US NHs.

PARTICIPANTS

We included all long-stay residents, aged 65 years or older, enrolled in Medicare from January 1, 2008, to December 31, 2009 (N = 1 257 279). Residents were followed from long-stay qualification until the first event of LE fracture, death, or end of follow-up (2 years).

MEASUREMENTS

Fractures were classified using Medicare diagnostic and procedural codes. Function, cognition, and medical status were obtained from the Minimum Data Set prior to long-stay qualification. Incidence rates (IRs) were calculated as the total number of fractures divided by person-years.

RESULTS

During 42 800 person-years of follow-up, 52 177 residents had an LE fracture (43 695 hip, 6001 femoral shaft, 2481 tibia-fibula). The unadjusted IRs of LE fractures were 1.32/1000 person-years (95% confidence interval [CI] = 1.27-1.38) for tibia-fibula, 3.20/1000 person-years (95% CI = 3.12-3.29) for femoral shaft, and 23.32/1000 person-years (95% CI = 23.11-23.54) for hip. As compared with hip fracture residents, non-hip LE fracture residents were more likely to be immobile (58.1% vs 18.4%), to be dependent in all activities of daily living (31.6% vs 10.8%), to be transferred mechanically (20.5% vs 4.4%), to be overweight (mean body mass index = 26.6 vs 24.0 kg/m² ), and to have diabetes (34.8% vs 25.7%).

CONCLUSIONS

Our findings that non-hip LE fractures often occur in severely functionally impaired residents suggest these fractures may have a different mechanism of injury than hip fractures. The resident differences in our study highlight the need for distinct prevention strategies for hip and non-hip LE fractures.

Facility and State Variation in Hip Fracture in U.S. Nursing Home Residents

OBJECTIVES

To quantify the variation in hip fracture incidence across U.S. nursing home (NH) facilities and states and examine how hip fracture incidence varies according to facility- and state-level characteristics.

DESIGN

Retrospective cohort using linked national Minimum Data Set assessments; Online Survey, Certification and Reporting records; and Medicare claims.

SETTING

U.S. NHs with 100 or more beds.

PARTICIPANTS

Long-stay NH residents between May 1, 2007, and April 30, 2008, from 1,481 facilities and 46 U.S. states (N = 201,892).

MEASUREMENTS

Incident hip fractures were ascertained using Medicare Part A diagnostic codes. Each resident was followed for up to 2 years.

RESULTS

The mean adjusted incidence rate of hip fractures for all facilities was 3.13 (95% confidence interval (CI) = 3.01-3.26) per 100 person-years (range 1.20, 95% CI = 1.15-1.26 to 6.40, 95% CI = 6.07-6.77). Facilities with the highest rates of hip fracture had greater percentages of residents taking psychoactive medications (top tertile 27.2%, bottom tertile 24.8%), and fewer nursing (top tertile 3.43, bottom tertile 3.53) and direct care (top tertile 3.22, bottom tertile 3.29) hours per day per resident. The combination of state and facility characteristics explained 6.7% of the variation in hip fracture, and resident characteristics explained 7.6%.

CONCLUSION

Much of the variation in hip fracture incidence remained unexplained, although these findings indicate that potentially modifiable state and facility characteristics such as psychoactive drug prescribing and minimum staffing requirements could be addressed to help reduce the rate of hip fracture in U.S. NHs.