Impact of drug classes used in COPD on outcome measures other than exacerbations

Many outcome measures are inherently variable. Bronchodilators appear to have a greater effect on FEV1 than on other outcomes, but this apparent sensitivity may be because FEV1 is the best least variable outcome and has be better repeatability between measurements. Theophylline is effective, but it has many side-effects. ICS may have benefecial effects on symptoms, HR-QoL and exacerbations, but only at high doses in severe patients. ICS are also association with side-effects.