TABLE 1

Baseline characteristics of patients with COPD with and without inhaled corticosteroid (ICS) withdrawal, before and after 1–2 propensity score (PS) matching and after stabilised inverse probability weighting (IPTW)

CharacteristicAll patients1–2 PS matchingStabilised IPTW
ICS withdrawal (n=971)Control (n=2764)smdICS withdrawal (n=904)Control (n=1808)smdICS withdrawal (n=872)Control (n=2591)smd
Males84.0%79.0%−12.9%84.0%82.0%−5.6%80.0%81.0%0.7%
Fiscal year
 20104.1%10.1%−23.6%4.1%3.9%1.1%7.3%8.3%−3.4%
 20119.4%17.0%−22.6%9.4%8.7%2.5%16.8%14.6%6.0%
 201213.8%20.2%−16.9%13.8%12.9%2.8%18.7%17.8%2.4%
 201318.3%18.4%−0.4%18.3%20.7%−6.3%16.3%18.6%−5.9%
 201425.0%19.9%12.4%25.0%25.2%−0.5%21.4%22.2%−1.9%
 201529.4%14.5%36.8%29.4%28.6%1.8%19.4%18.6%2.1%
Season at admission
 Spring23.7%24.9%−2.8%23.7%24.3%−1.4%23.6%24.0%−1.0%
 Summer24.4%22.2%5.4%24.4%25.1%−1.5%23.3%23.3%0.1%
 Autumn24.4%23.1%3.1%24.4%24.8%−0.8%24.2%24.2%0.1%
 Winter27.4%29.8%−5.3%27.4%25.8%3.6%28.9%28.5%0.8%
Residential region
 Hokkaido and Tohoku10.1%10.6%−1.8%10.1%10.2%−0.5%8.8%10.8%−6.6%
 Kanto30.6%35.6%−10.6%30.6%29.9%1.7%36.2%34.1%4.5%
 Chubu15.7%15.7%0.0%15.7%14.8%2.5%13.9%15.2%−3.7%
 Kansai16.0%16.0%0.2%16.0%16.1%−0.2%14.6%15.4%2.1%
 Chugoku, Shikoku, Kyushu and Okinawa27.5%22.0%12.8%27.5%29.0%−3.2%26.4%24.5%4.3%
Hugh–Jones dyspnoea score at admission
 110.8%9.5%4.3%10.8%11.2%−1.2%9.6%9.5%0.2%
 2–333.7%32.2%3.2%33.7%30.9%6.0%32.7%32.7%0.0%
 4–545.7%51.8%−12.3%45.7%48.2%−5.1%50.9%50.3%1.2%
 Missing9.7%6.4%12.2%9.7%9.6%0.4%6.8%7.5%−2.6%
ADL at admission (Barthel Index score)
 10037.1%37.9%−1.7%37.1%35.0%4.3%35.4%37.4%−4.1%
 0–9049.0%46.4%5.2%49.0%50.8%−3.7%48.4%47.6%1.5%
 Missing13.9%15.7%−5.0%13.9%14.2%−0.6%16.2%15.0%3.4%
ADL at discharge (Barthel Index score)
 10055.4%62.4%−14.3%55.4%53.4%4.1%57.8%59.8%−4.0%
 0–9036.0%29.8%13.2%36.0%36.7%−1.6%34.7%31.9%6.1%
 Missing8.6%7.8%3.1%8.6%9.9%−4.4%7.4%8.3%−3.2%
Smoking index
 200–5999.0%9.8%−2.8%9.0%7.5%5.2%8.9%9.3%−1.2%
 ≥60049.4%48.3%2.3%49.4%49.8%−0.7%48.3%49.3%−2.1%
 Missing41.6%41.9%−0.7%41.6%42.7%−2.2%42.8%41.4%2.9%
Age years77.8±7.076.9±6.613.977.8±7.078.1±6.9−4.277.5±7.177.2±6.70.4
Body mass index kg·m−220.5±3.921.3±4.0−19.920.5±3.920.3±3.73.420.8±4.121.0±4.0−4.1
Frequency of hospitalisation before hospitalisation for COPD exacerbation0.84±1.30.59±1.218.50.84±1.30.98±2.1−8.10.83±1.20.77±1.64.4
Observation period before hospitalisation for COPD exacerbation days1055.4±574.0847.0±571.335.91058.2±576.71055.4±610.10.5912.7±567.4913.9±587.4−0.2

Data are presented as mean±sd unless otherwise stated. smd: standardised mean difference; ADL: activities of daily living.