• COPD exacerbations

We read with interest the article by Gonzalez et al1 on gender differences in survival following hospitalisation of chronic obstructive pulmonary disease (COPD) patients in a large cohort of a Canadian population. There are limited data on gender differences and mortality in COPD. Despite women having worse dyspnoea and health status, they appear to have a lower mortality rate than men.2 The study conducted by Gonzalez and coworkers demonstrated an interesting finding of a significantly better mean survival and time to rehospitalisation in female patients. We conducted a study of COPD patients to evaluate the predictors of mortality and readmission after an acute exacerbation.3 The study included 402 episodes in 205 patients admitted to our university hospital. We examined a number of factors in relation to mortality and readmission after an exacerbation. The potential predictors evaluated in the study included FEV₁% predicted, Medical Research Council dyspnoea scale, performance status, respiratory medications, comorbidities, social circumstances, smoking status and blood parameters including white cell count and C reactive protein. The main demographics and characteristics of the study population are shown in table 1.

The cumulative mortality of our study population was 6.8%. In terms of the cause of death, the majority of our study population died of respiratory causes, predominantly COPD, a finding very similar to that found by Gonzalez et al. Men had a higher rate of admissions than women, comprising 56% of total hospitalisation episodes. Social isolation was the only significant predictor of mortality in our cohort. Reduced physical activity in association with social isolation may be related to increased mortality. The factors associated with increased risk of readmission included lower FEV₁% predicted and continued smoking. Contrary to the findings of Gonzalez et al, we found no significant difference in mortality in relation to gender, following hospitalisation for COPD. This could be because of a number of factors. First, we had a significantly smaller sample size. Second, our study may have represented a different population altogether with diversity in ethnic background and genetic makeup. Finally, the patients were younger in our cohort that may have had an effect on the overall mortality.

In our opinion, Gonzalez and coworkers have evaluated a very unique aspect of COPD outcome after hospitalisation. The immediate period after an acute exacerbation is a very significant time for interventions such as smoking cessation, and if utilised effectively, it may have a positive impact on mortality in this disabling disease.