Prevalence and predictors of vertebral fracture in patients with chronic obstructive pulmonary disease☆

Summary 

Objectives

Patients with COPD are at risk for osteoporosis-related vertebral compression fractures (VCF) which predispose to more fractures and worsening pulmonary function. Our objectives were to: 1 document VCF prevalence in COPD patients; and 2 determine the independent correlates of VCF.

Methods

From 2004–2006, we prospectively recruited consecutive consenting COPD patients presenting with acute exacerbation at three Canadian Emergency Departments (ED). We collected clinical and pulmonary function data. Primary outcome was radiologist documented VCF on chest radiograph. Multivariable logistic regression was used for all adjusted analyses.

Results

Overall, 245 patients were studied; 37% were ≥75 years and 44% were women. Prevalence of VCF documented by chest radiograph was 22 of 245 (9%; 95%CI 6–13%). Almost half (10 of 22 [43%]) of VCF patients were not treated for osteoporosis and all 10 received oral steroids. Compared to patients without fractures, those with VCF were older (p=0.014), had COPD of longer duration (p=0.09) and greater severity (mean FEV₁ 0.9 vs 1.1L; p=0.05), and had lower body mass index [BMI] (median 26 vs 28; p=0.01). Across BMI quartiles (from heaviest [median 37] to lightest [median 21]) the prevalence of VCF progressively increased (2%, 8%, 10%, 21%; p<0.001). In analyses adjusted for age, sex, and COPD duration, the only independent correlate of VCF was BMI: VCF increased as BMI decreased from heaviest (OR=1) to lightest (OR=11.0) quartiles (p=0.025).

Conclusions

Almost one-tenth of COPD patients presenting with acute exacerbation have chest radiographs documenting VCF. About half of patients with VCF were not treated for osteoporosis, but all were started on oral steroids. Our findings suggest chest radiograph reports may represent an important case-finding tool for VCF, particularly in underweight patients with COPD.

Keywords: COPD, Osteoporosis, Vertebral fractures, Risk factors, Clinical epidemiology