Functional capacity and dyspnea during follow-up after acute pulmonary embolism

BACKGROUND

Dissecting the determinants of functional capacity during long-term follow-up after acute pulmonary embolism (PE) can help to better characterize a patient population with persisting limitation.

METHODS

In a prospective cohort study, consecutive unselected survivors of acute PE underwent 3- and 12-month follow-up, including six-minute walking distance (6MWD) and dyspnea assessment with the modified Medical Research Council (mMRC) scale. We used reference equations adjusting for age, sex, and anthropometric measurements to define abnormal 6MWD.

RESULTS

Overall, 323 of 363 (89.0%) patients had at least one recorded 6MWD value at one year. At 3 months, the prevalence of abnormal 6MWD was 21.9% and at 12 months it was 18.3%. At 3 and 12 months, 58.8% and 52.1% with abnormal 6MWD did not report dyspnea, respectively. On average and during follow-up, 6MWD significantly improved with time, while the mMRC dyspnea scale did not. Abnormal 6MWD was associated with younger age (odds ratio per decade, 0.91; 95% CI, 0.88-0.94), higher body mass index (1.10; 1.03-1.17), smoking (3.53; 1.34-9.31), intermediate- or high-risk PE (3.21; 1.21-8.56), and higher mMRC grading (2.28; 1.59-3.27). Abnormal 6MWD at 3 months was associated with the prospectively defined endpoint of post-PE impairment (3.72; 1.50-9.28) and with poor disease-specific and generic health-related quality of life.

CONCLUSION

Three months after PE, 37% of patients reported dyspnea and 22% had abnormal 6MWD. After a year, 20% still had abnormal 6MWD. Dyspnea correlated with abnormal 6MWD, but over 50% of patients with abnormal 6MWD did not report dyspnea. Abnormal 6MWD predicted subsequent post-pulmonary embolism impairment and worse long-term quality of life.

CLINICAL TRIAL REGISTRATION

German Clinical Trials Register Identifier DRKS00005939.

A randomized placebo-controlled phase 3 trial of an antisense oligonucleotide, drisapersen, in Duchenne muscular dystrophy

This 48-week, randomized, placebo-controlled phase 3 study (DMD114044; NCT01254019) evaluated efficacy and safety of subcutaneous drisapersen 6 mg/kg/week in 186 ambulant boys aged ≥5 years, with Duchenne muscular dystrophy (DMD) resulting from an exon 51 skipping amenable mutation. Drisapersen was generally well tolerated, with injection-site reactions and renal events as most commonly reported adverse events. A nonsignificant treatment difference (P = 0.415) in the change from baseline in six-minute walk distance (6MWD; primary efficacy endpoint) of 10.3 meters in favor of drisapersen was observed at week 48. Key secondary efficacy endpoints (North Star Ambulatory Assessment, 4-stair climb ascent velocity, and 10-meter walk/run velocity) gave consistent findings. Lack of statistical significance was thought to be largely due to greater data variability and subgroup heterogeneity. The increased standard deviation alone, due to less stringent inclusion/exclusion criteria, reduced the statistical power from pre-specified 90% to actual 53%. Therefore, a post-hoc analysis was performed in 80 subjects with a baseline 6MWD 300-400 meters and ability to rise from floor. A statistically significant improvement in 6MWD of 35.4 meters (P = 0.039) in favor of drisapersen was observed in this subpopulation. Results suggest that drisapersen could have benefit in a less impaired population of DMD subjects.

Effects of Tai Chi on exercise capacity and health-related quality of life in patients with chronic obstructive pulmonary disease: a systematic review and meta-analysis

BACKGROUND

Tai Chi is a traditional Chinese mind-body exercise that has been widely practiced in the People's Republic of China for many centuries. This exercise has also been applied as a training modality in pulmonary rehabilitation programs for stable chronic obstructive pulmonary disease (COPD). This systematic review and meta-analysis aimed to assess the effects of Tai Chi on exercise capacity and health-related quality of life (HRQoL) in COPD patients.

METHODS

Electronic databases (PubMed, Embase, Web of Science, The Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, ClinicalTrials.gov, China National Knowledge Infrastructure, and China Biology Medicine disc) were searched. Entries published from January 1980 to March 2014 were included in the search. Eligible studies included those that involved randomized controlled trials and those that lasted for at least 12 weeks. The primary outcome measures were six-minute walking distance (6 MWD), St George's Respiratory Questionnaire (SGRQ), and Chronic Respiratory Disease Questionnaire (CRQ). Effect estimates were pooled with random-effects meta-analysis.

RESULTS

Eleven articles involving 824 patients met the inclusion criteria. All included articles compared COPD patients in a Tai Chi group versus COPD patients in nonexercise and/or physical exercise groups. The meta-analysis showed that compared with the nonexercise group, the COPD patients practicing Tai Chi demonstrated significantly enhanced 6 MWD (mean difference 35.99, 95% confidence interval [CI] 15.63-56.35, P=0.0005), decreased SGRQ total score (mean difference -10.02, 95% CI -17.59, -2.45, P=0.009), and increased CRQ total score (mean difference 0.95, 95% CI 0.22-1.67, P=0.01). Compared with the physical exercise group, the Tai Chi group showed significantly reduced SGRQ total score (mean difference -3.52, 95% CI -6.07, -0.97, P=0.007), but no statistical significance was found for 6 MWD between the two groups (mean difference 13.65, 95% CI -1.06, 28.37, P=0.07) in COPD patients.

CONCLUSION

Preliminary evidence suggests that Tai Chi has beneficial effects on exercise capacity and HRQoL in COPD patients. This exercise can be recommended as an effective alternative training modality in pulmonary rehabilitation programs. Further studies are required to support the preliminary evidence and to observe the long-term effects of Tai Chi.

Functional and psychological variables both affect daily physical activity in COPD: a structural equations model

BACKGROUND

Daily physical activity (DPA) level is reduced in patients with COPD. The aim of this study was to investigate the association of DPA with functional and psychological variables in these patients.

METHODS

155 COPD patients (102 males, median (IQR) age 62 years (54-69 years), predicted FEV1 60% (40-75%) were included. We assessed DPA (DigiWalker SW-200), functional capacity and psychological factors.

RESULTS

DPA level was significantly associated with all functional capacity variables and two psychological variables (Perceived Physical Ability Subscale, depression subscale of the Hospital Anxiety and Depression Scale). The six-minute walking distance and St. George Respiratory Questionnaire activity score explained 37% of the variance of DPA in a regression analysis. A structural equations model revealed that psychological variables indirectly explained DPA through functional capacity variables. DPA was stronger associated with functional capacity variables and weaker with psychological variables in patients with lower functional status than in patients with higher functional status.

CONCLUSIONS

Higher levels of DPA are associated with better functional capacity, but interestingly, DPA is also affected by psychological factors, though only indirectly, via functional capacity. The effect of specific treatment addressing psychological factors on DPA level and exercise tolerance needs further investigation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT00614796.