Baseline characteristics of the study population.

<p>Data are number (%) unless otherwise indicated. OPD: obstructive pulmonary disease.</p>1<p>Drug use at index date.</p>2<p>Drug use at index date, or within six months prior to index date.</p>3<p>Use of systemic corticosteroids with a duration of 90 days or more.</p>4<p>Use of any of the following drugs: β-adrenoreceptor blockers, calcium channel antagonists, angiotensin converting enzyme inhibitors, diuretics, angiotensin-II receptor blockers, nitrates, platelet aggregation inhibitors, and statins, within six months prior to index date.</p>5<p>Use of anti-diabetics within six months prior to index date.</p>6<p>Class I and III antiarrhythmic drugs and non-antiarrhythmic drugs with (possible) risk of QT prolongation (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065638#pone.0065638.s001" target="_blank">Table S1</a>).