A 5-Item Frailty Index Based on NSQIP Data Correlates with Morbidity and Mortality Following Paraesopahgeal Hernia Repair

Munyaradzi Chimukangara, MD¹, Matthew Frelich, MS¹, Matthew Bosler, BA¹, Lisa Rein, MS², Aniko Szabo, PhD², Jon Gould, MD¹. ¹Medical College of Wisconsin, Surgery, ²Medical College of Wisconsin, Biostatistics

Introduction: Frailty is a measure of physiologic reserve associated with increased vulnerability to adverse outcomes following surgery in the elderly.  The ‘accumulating deficits’ model of assessing frailty has been applied to the ACS NSQIP database, and an 11-item modified frailty index (mFI) has been developed and validated. Unfortunately, many of the 11 variables in this mFI are often missing from the NSQIP data, significantly decreasing the sample size for less commonly performed procedures.  We developed a condensed 5-point frailty index based on the larger 11-point scale to assess the relationship between frailty and outcomes in patients undergoing paraesophageal hernia (PEH) repair.

Methods: The NSQIP database was queried for ICD-9 and CPT codes associated with PEH repair.  The NSQIP participant use files for the years 2011-2013 were utilized.  Only subjects ≥ 60 years old were included. Frailty was assessed based on the number of variables mapped to the 5-point frailty index (0, 1, 2, ≥ 3 items present). Outcomes were 30-day mortality, Clavien-Dindo Grade ≥ 3 complications, discharge destination, and readmissions. Multivariate logistic regression was used to determine the relationship between frailty and outcomes.

Results: Of the 4434 eligible patients, 3711 records were included in the final analysis (84%). Excluded patients were missing 1 or more variables in the 5-point frailty index.  Additional analysis revealed that using the 11-point mFI, only 885 patients (20%) would have been included based on missing data. Clavien-Dindo Grade ≥ 3 complications were 5.9%, mortality 1.2%, readmission 7.6%, and 8.7% of patients were discharged to a facility other than home. The 5-point frailty index was significantly correlated with complications [p <0.0001], mortality [p <0.0007], discharge to a facility other than home [p <0.0001], and readmissions [p <0.0184].

Conclusions: Frailty, as assessed by a condensed 5-point frailty index is significantly correlated with adverse outcomes in patients undergoing PEH repair. When compared to the original 11-point mFI, the utilization of the 5-point index allows for a significantly increased sample size and a cohort that is likely more representative of the study group of interest (84% vs. 20% of otherwise eligible patients).  Further study is necessary to determine if the condensed 5-point mFI is a valid measure of frailty.