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

Abstract

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.

Figure 1

Clinical and functional status on days with heat stress vs. thermal comfort. Box plots showing a) CAT Score, b) FEV₁ (%) and c) 6MWT steps on 32 days with Temp_max > 25°C compared to 32 days with Temp_max ≤ 25°C. Statistical significance is set at P < 0.05.

Figure 2

Variation in daily clinical status and lung-function in response to outside temperature. Dual axis box plots with the x-axis depicting a) FEV₁ (ml) and b) CAT score. The y-axis indicates the days from June–31^st August and the z-axis (black line) shows daily temperature fluctuations.

Figure 3

Bar graph showing the number of exacerbation from June–August 2012 in the Telegroup (TG = grey boxes, N = 3) and the Control Group (CG = black boxes, N = 14) with corresponding date of event on the x-axis and daily T _max in °C on the y-axis.

Figure 4

Bar graph representing number of exacerbations (light grey), visits to the primary care physician (medium grey) and to the lung specialist (dark grey) in the Telegroup (TG, N = 32) versus the Control Group (CG, N = 30). Statistical significance is set at P < 0.05.