Patterns and predictors of low physical activity in patients with stable COPD: a longitudinal study

Background:

Despite the frequency and negative impact of low physical activity among patients with chronic obstructive pulmonary disease (COPD), little is known about how it persists and remits over time or the factors predicting new states of low physical activity. The aim of the study was to determine the probability of a transition between states of low and nonlow physical activity in a cohort of patients with stable COPD followed for 2 years. We also investigated different potentially modifiable factors to determine whether they can predict new states of low physical activity.

Methods:

We prospectively included 137 patients with stable COPD (mean age 66.9 ± 8.3 years). Physical activity was measured at baseline and at 1 and 2 years of follow up. Low physical activity was defined according to energy expenditure by cut-off points from the Fried frailty model. The likelihood of annual transition towards new states and recovery was calculated. We evaluated demographic, frailty, nonrespiratory, and respiratory variables as potential predictors, using generalized estimating equations.

Results:

At baseline, 37 patients (27%) presented with low physical activity. During the study period, a total of 179 annual transitions were identified with nonlow physical activity at the beginning of the year; 17.5% transitioned to low physical activity. In contrast, 34.3% of the 67 transitions that started with low physical activity recovered. Predictors of transition to new states of low physical activity were dyspnea ⩾2 (odds ratio = 3.21; 95% confidence interval: 1.20–8.61) and poor performance on the five sit-to-stand test (odds ratio = 4.75; 95% confidence interval: 1.30–17.47).

Conclusions:

The change between levels of low and nonlow physical activity is dynamic, especially for recovery. Annual transitions toward new states of low physical activity are likely among patients with dyspnea or poor performance on the five sit-to-stand test.

The reviews of this paper are available via the supplemental material section.

Frailty transitions and associated clinical outcomes in patients with stable COPD: A longitudinal study

BACKGROUND

Although frailty is a frequent occurrence in chronic obstructive pulmonary disease (COPD) patients, evidence on the frequency of frailty transition is scarce.

AIMS

The present study aimed to describe the frailty status transition rates over a 2-year period and their associated clinical outcomes in stable COPD patients, and to determine predictors of improvement in frailty status.

METHODS

We prospectively included 119 patients with stable COPD (mean age ± SD, 66.9 ± 7.9 years) over a follow-up period of 2 years. Frailty was assessed using the Fried criteria (unintentional weight loss, weakness, exhaustion, low activity level, and slow walking speed). Several demographic, clinical, and health-related variables were measured. We calculated the rates for each of the frailty transitions (no change, improvement, or worsening) between baseline and 2 years. Outcomes were compared using one-way analysis of variance and predictors of improvement were identified in multivariate logistic regression.

RESULTS

After 2 years of follow-up, 21 (17.6%) patients had an improved frailty status, 14 (11.7%) had worsened, and 84 (70.5%) had maintained the same frailty status. The worsening group (vs no change group) had greater dyspnea (p = 0.013) and disability (p = 0.036) and lower handgrip strength (p = 0.001). In contrast, the improved group (vs no change group) had greater handgrip (p<0.001) and quadriceps strength (p = 0.032). Furthermore, the improved group had greater handgrip strength (p<0.001), quadriceps strength (p = 0.003), physical activity (p = 0.008), and lower disability (p = 0.019) than the worsening group. Additionally, we determined that the 5STS test (≤ 13.6s) and exacerbations (≥ 2) were independent predictors for improvement in frailty status [adjusted OR 9.46, p = 0.058 and adjusted OR 0.12, p = 0.026, respectively].

CONCLUSIONS

Frailty is a dynamic process for approximately one-third of patients with stable COPD and transitions in frailty status are associated with significant changes in clinical outcomes. The 5STS and exacerbations were independent predictors of improvement in frailty status.

[Structure and metric properties of a questionnaire to measure disability in mobility activities in patients with chronic obstructive pulmonary disease (DIAMO-COPD questionnaire)]

OBJECTIVE

The aim of this study was to adapt a disability questionnaire in mobility activities (DIAMO-EPOC) incorporating scales based on the conceptual framework of the International Classification of Functioning, Disability and Health, and to examine its structure, reliability and validity in a cohort of patients with COPD.

METHODS

A total of 137 patients with stable COPD were recruited. Two scales of 4 items each were designed and their structure was verified by exploratory factor analysis and multitrait scaling analysis. Additionally, reliability indices (internal consistency and test-retest) were calculated. Construct validity was analysed by known groups and convergence-divergence.

RESULTS

The questionnaire had 2 scales, with 4 items each, corresponding to the domains of the International Classification of Functioning, Disability and Health "change and maintain the position of the body" and "walk and move". The reliability and internal consistency of the scales were acceptable and the test-retest was excellent with an ICC of 0.86 and 0.94, respectively. The scales showed a moderate association with dyspnoea, health status and muscle strength and a different score among participants with different physical performance in the Short Physical Performance Battery.

CONCLUSIONS

The 2 scales of the DIAMO-EPOC questionnaire are one-dimensional and have a solid internal consistency, test-retest stability and validity, allowing the identification of specific areas of limited mobility in patients with COPD.

Patterns and predictors of exhaustion episodes in patients with stable COPD: A longitudinal study

BACKGROUND AND OBJECTIVE

Exhaustion is the perception of low energy. Little is known about how exhaustion persists, remits or reappears over time in patients with chronic obstructive pulmonary disease (COPD) or how to predict these events. We determined the likelihood of transitions between states of exhaustion and no exhaustion among patients with stable COPD followed up for 2 years. We investigated combinations of potential factors for their abilities to predict new-onset exhaustion episodes.

METHODS

We prospectively included 137 patients with stable COPD (mean age, 66.9 years ± 8.3). Exhaustion states were measured at baseline and 1 and 2 years later. Exhaustion was defined as an answer of "most of the time" or "a moderate amount of time" to 1 of 2 questions: "How often have you found it hard to get going?" and "How often does everything seem to require effort?" We evaluated demographic, non-respiratory and respiratory variables as potential predictors. The likelihoods of new episodes and recovery were calculated. Predictors were evaluated with generalised estimating equations.

RESULTS

At baseline, 27 patients (19.7%) displayed exhaustion. Of the 110 patients without exhaustion at baseline, 17 (15.5%) displayed exhaustion at least once during the follow-up period. During the study period, a total of 204 annual transitions displaying no exhaustion at the beginning were identified. Of them, 10.3% transitioned to exhaustion in the next year. The likelihood of recovery after exhaustion was 50%. Independent predictors of new-onset exhaustion episodes within the following year were: the COPD assessment test score (odds ratio [OR] = 1.10; 95% confidence interval [CI] 1.01-1.21), depression (OR = 6.89; 95% CI: 1.00-47.41) and female gender (OR = 6.88; 95% CI: 1.83-25.73).

CONCLUSIONS

Patients in stable COPD with high CAT scores and depression were most likely to experience new-onset exhaustion episodes Thus, exhaustion might be predicted by a combination of psychological factors and respiratory health status. Nevertheless, exhaustion is dynamic in COPD; half of patients recover from exhaustion.