Heat stress is associated with reduced health status in pulmonary arterial hypertension: a prospective study cohort.

BACKGROUND: Summer heat waves with temperature extremes are becoming more frequent with growing numbers in morbidity and mortality in patients with respiratory diseases. The aim of this study was to evaluate the ramifications of heat stress (temperature >25 °C) on the health status of patients with pulmonary arterial hypertension (PAH). METHODS: Fifteen patients with PAH (mean age = 66.7 ± 5.2 years) continuously wore an accelerometer from April 1 to September 30, 2011, and their daily step count was recorded. In addition, patients kept a diary to record data on seven standardized questions regarding their daily symptoms. Echocardiography, 6-minute walk test, NTproBNP, and Modified Medical Research Council Scale (MMRC) were assessed at baseline and at the end of the study after 6 months. RESULTS: On heat-stress days, patients showed significantly more symptoms and lower total steps/day compared to thermal comfort days (3,995 ± 2,013 steps/day vs. 5,567 ± 2,434 steps/day, respectively; P < 0.001). There was a significant negative correlation between total steps/day and Temp(max) (R = -0.47; P < 0.001) and humidity (R = -0.34; P < 0.001). A significant positive correlation was found between daily symptoms and Temp(max) (R = +0.79; P < 0.001) and humidity (R = +0.23; P < 0.001). CONCLUSIONS: Heat stress is associated with a compromised clinical status in patients with PAH. Adaptation strategies must be implemented to prevent heart-related morbidity, including therapeutic adjustments and adequate room cooling in the patient's home and at the hospital.

Tele-monitoring reduces exacerbation of COPD in the context of climate change--a randomized controlled trial.

BACKGROUND: A home based tele-monitoring system was developed to assess the effects of heat stress (days > 25°C) on clinical and functional status in patients with chronic obstructive pulmonary disease (COPD). METHODS: Sixty-two COPD patients (GOLD II-IV) were randomized into a tele-monitoring Group (TG, N = 32) or Control Group (CG, N = 30). Tele-monitoring included 1) daily clinical status (COPD Assessment Test-CAT), 2) daily lung function and 3) weekly 6-minute walk test (6MWT). Duration of monitoring lasted a total of nine months (9 M). RESULTS: From June 1st-August 31st 2012, 32 days with heat stress (29.0 ± 2.5°C) were recorded and matched with 32 thermal comfort days (21.0 ± 2.9°C). During heat stress, the TG showed a significant reduction in lung function and exercise capacity (FEV1% predicted: 51.1 ± 7.2 vs. 57.7 ± 5.0%; P <0.001 and 6MWT performance: 452 ± 85 vs. 600 ± 76 steps; P <0.001) and increase in CAT scores (19.2 ± 7.9 vs. 16.2 ± 7.2; P <0.001).Over summer, significantly fewer TG patients suffered exacerbation of COPD compared to CG patients (3 vs. 14; P = 0.006). Over entire 9 M follow-up, the TG group had fewer exacerbations compared to CG (7 vs. 22; P = 0.012), shorter cumulative hospital stay (34 vs. 97 days) and 43% fewer specialist consultations (24. vs. 42; P = 0.04). CONCLUSION: Heat stress affects clinical and functional status in COPD. Tele-monitoring reduces exacerbation frequency and health care utilization during heat stress and other periods of the year. TRIAL REGISTRATION DRKS-ID: DRK00000705.