Relationship Between Mortality and BMI After Fracture: A Population-Based Study of Men and Women Aged ≥40 Years

Abstract

Fractures in obese older individuals contribute significantly to the overall burden on primary health care, but data on their impact on mortality are lacking. We studied the association between obesity and mortality following hip and nonhip clinical fractures in a retrospective, population-based cohort study. The Sistema d'Informacio pel Desenvolupament de la Investigacio en Atencio Primària (SIDIAP Q ) database contains primary care computerized medical records of a representative sample of >2.1 million people (35% of the population) in Catalonia (Spain), linked to hospital admissions data. We included in this analysis anyone aged 40 years and older suffering a hip or nonhip clinical fracture in 2007 to 2009 in the SIDIAP Q database. The main exposure was the most recent body mass index (BMI) measured before fracture, categorized as underweight (<18.5 kg/m 2 ), normal (18.5 to <25 kg/m 2 ), overweight (25 to <30 kg/m 2 ), and obese (!30 kg/m 2 ). Furthermore, the study outcome was all-cause mortality in 2007 to 2009 as provided to SIDIAP Q by the National Office of Statistics. Time to death after fracture was modeled using Cox regression. Multivariate models were adjusted for age, gender, smoking, alcohol intake, oral glucocorticoid use, and Charlson comorbidity index. Within the study period, 6988 and 29,372 subjects with a hip or nonhip clinical fracture were identified and followed for a median (interquartile range) of 1.17 (0.53-2.02) and 1.36 (0.65-2.15) years, respectively. Compared to subjects of normal weight, adjusted hazard ratios (HRs) for mortality in overweight and obese subjects were 0.74 (95% CI, 0.62-0.88; p ¼ 0.001) and 0.74 (95% CI, 0.60-0.91; p ¼ 0.004) after hip and 0.50 (95% CI, p ¼ 0.002), 0.56 (95% CI,; p ¼ 0.010) after nonhip fracture. In conclusion, the highest mortality was observed in individuals with low BMI, but compared to subjects of normal weight, obese and overweight individuals survived longer following fracture. The latter observation is consistent with data reported in other chronic conditions, but the reasons for reduced mortality in obese and overweight subjects when compared to those of normal weight require further research.

Obesity and fractures

“…Analyzing the population health database from the family strategy program SIDIAP ® (Catalunya, Spain), Prieto-Alhambra and cols., described longer survival of overweight and obese individuals than normal weight subjects (18.5 to < 25 kg/m 2 ) after incident clinical fracture (57). This observation is consistent with other reports of the "obesity paradox" in conditions such as congestive cardiac failure, chronic renal insufficiency and chronic obstructive pulmonary disease (58)(59)(60)(61).…”

Obese trauma patients who sustain orthopaedic fractures experience increased length of stay, ICU admissions and mortality

“…Recent literature suggests that obesity is protective against hip fractures and is associated with decreased mortality, the so called "obesity paradox" [36][37][38][39][40]. However, an analysis conducted across fracture sites in this study demonstrated that isolated femoral neck fractures were signifi cantly associated with mortality in this cohort of orthopaedic trauma patients.…”

Obesity Paradox, Obesity Orthodox, and the Metabolic Syndrome: An Approach to Unity

“…Because obese and overweight patients often fare better than their normal-weight counterparts, the tag "obesity paradox" has often been applied. As shown in Figures 8A and B, obese patients who have uninfected fractures of the hip or other bones show better outcomes that are reminiscent of those observed with so-called unconquerable infections (48). Valentijn et al compiled a collection of published reports of surgical entities and a similar collection of nonsurgical entities where patients with above-normal adiposity show better outcomes (49,50).…”