Patients with chronic obstructive pulmonary disease (COPD) who have a preserved physical capacity seem to have a significantly lower 6-year risk for mortality compared with those who have a decreased physical capacity, regardless of their level of physical activity. These were among the findings of a retrospective study, recently published in Chest, which was conducted at 3 hospitals in The Netherlands.

Recognizing that physical capacity (“can do”) and physical activity (“do do”) are prognostic indicators in COPD that can be used to subdivide patients into 4 exclusive subgroups (ie, the “can do, do do” quadrants), the researchers sought to explore the

Six-year all-cause mortality risk in the “can do, do do” quadrants among patients with COPD. All patients underwent a comprehensive evaluation at their first-ever outpatient consultation. Data from patients with a pulmonologist-confirmed diagnosis of COPD were used. All patients completed a comprehensive standardized health status assessment as part of their usual COPD care at Amphia Hospital (Breda, The Netherlands); Bernhoven Hospital (Uden, The Netherlands); or Radboud University Medical Centre (Nijmegen, The Netherlands) between April 2012 and January 2019.


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Patients’ physical capacity was evaluated with use of the 6-minute walk distance (6MWD); physical activity was assessed via use of an accelerometer (measuring steps per day). The Municipal Personal Records Database was used to obtain all-cause mortality data. Threshold values for physical capacity and physical activity were established with the use of receiver operating characteristic curves, in order to predict 6-year all-cause mortality rates. The derived threshold values were utilized to divide the male and female patients into the 4 “can do, do do” quadrants.

The analysis included data from 829 patients (54% men; average age 64±9 years). Patients had mild to very severe COPD, with an impaired physical capacity (6MWD, 68±16% predicted) and a low physical activity level (5556±3339 steps per day). The best discriminatory values for 6-year mortality were 404 meters (physical capacity) and 4125 steps per day (physical activity) for men, and 394 meters and 4005 steps per day for women. Over a median follow-up of 55 months, 15.6% (129 of 829) of the patients died.

After adjustment for age, FEV1, Medical Research Council (MRC) dyspnea score, and BMI, male patients in the “can do, don’t do” and the “can do, do do” quadrants exhibited a significantly lower risk for mortality compared with male patients in the “can’t do, do do” quadrant (hazard ratio [HR], 0.36; 95% CI, 0.14-0.93 vs HR, 0.24; 95% CI, 0.09-0.61, respectively) and those in the “can’t do, don’t do” quadrant (HR, 0.39; 95% CI, 0.18-0.86 vs HR, 0.26; 95% CI, 0.11-0.58, respectively). No significant difference was reported between male patients in the “can’t do, do do” quadrant and those in the “can’t do, don’t do” quadrant (HR, 1.08; 95% CI, 0.50-2.36; P =.844) or between male patients in the “can do, don’t do” quadrant and those in the “can do, do do” quadrant (HR, 1.51; 95% CI, 0.61-3.75; P =.375).

In a similar fashion, after adjustment for age, FEV1, MRC dyspnea score, and BMI, female patients in the “can do, don’t do” and the “can do, do do” quadrants exhibited a significantly lower risk for mortality compared with female patients in the “can’t do, do do” quadrant (hazard ratio [HR], 0.37; 95% CI, 0.38-0.99 vs HR, 0.29; 95% CI, 0.10-0.87, respectively) and those in the “can’t do, don’t do” quadrant (HR, 0.19; 95% CI, 0.04-0.84  vs HR, 0.15; 95% CI, 0.06-0.40, respectively). No significant difference was reported between female patients in the “can’t do, do do” quadrant and those in the “can’t do, don’t do” quadrant (HR, 0.52; 95% CI, 0.22-1.24; P =.141) or between female patients in the “can do, don’t do” quadrant and those in the “can do, do do” quadrant (HR, 1.27; 95% CI, 0.26-6.30; P =.771).

The investigators concluded that 6-year all-cause mortality rates were significantly lower among patients with COPD who attended their first-ever outpatient consultation with a preserved physical capacity compared with those with a reduced physical capacity, regardless of an individual’s level of physical activity.

Reference  

Vaes AW, Spruit MA, Koolen EH, et al. “Can do, do do” quadrants and 6-year all-cause mortality in patients with COPD. Chest. Published online January 10, 2022. doi:10.1016/j.chest.2021.12.657

This article originally appeared on Pulmonology Advisor