[Long-term trials assessing pharmacological treatments in COPD: lessons and limitations].
BACKGROUND
Several long-term studies designed to assess pharmacological treatments for Chronic Obstructive Pulmonary Disease (COPD) have been published recently. Only such long-term studies allow an accurate analysis of the effect of treatments on criteria of effectiveness such as survival or decline in pulmonary function. A review of these studies is opportune.


BACKGROUND
The high drop out rate, which is not a random event, leads to serious methodological problems that are of importance in the interpretation of these studies. Post hoc analysis of both the TORCH and UPLIFT trials suggest a positive effect of long-acting bronchodilators on survival. Up to now, no treatment has convincingly demonstrated an effect on the rate of decline of FEV(1). The treatments evaluated lead to a decrease in exacerbation rates and an improvement in quality of life although the effects of inhaled corticosteroids are subject to methodological concerns. The treatments are all well tolerated.


CONCLUSIONS
The design of future studies should avoid the withdrawal of treatments at enrolment into a study in order to limit the number of drop outs.


CONCLUSIONS
Long-term studies have made important progress in the knowledge, not only of the effects of the treatments assessed but also of the methodological issues which need to be addressed.
Marchand
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Service de pneumologie, cliniques universitaires de Mont-Godinne, université catholique de Louvain, 1, avenue du Dr Therasse, 5530 Yvoir, Belgique. eric.marchand@uclouvain.be
D000280:Administration, Inhalation; D000305:Adrenal Cortex Hormones / Q000009:adverse effects / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000420:Albuterol / Q000009:adverse effects / Q000031:analogs & derivatives / Q000627:therapeutic use; D000730:Androstadienes / Q000009:adverse effects / Q000627:therapeutic use; D001993:Bronchodilator Agents / Q000009:adverse effects / Q000627:therapeutic use*; D019819:Budesonide / Q000009:adverse effects / Q000627:therapeutic use; D003131:Combined Modality Therapy; D004359:Drug Therapy, Combination; D005260:Female; D000068298:Fluticasone; D006801:Humans; D009241:Ipratropium / Q000009:adverse effects / Q000627:therapeutic use; D008134:Long-Term Care; D008297:Male; D008875:Middle Aged; D011241:Prednisone / Q000009:adverse effects / Q000627:therapeutic use; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy*; D016032:Randomized Controlled Trials as Topic; D000068299:Salmeterol Xinafoate; D012602:Scopolamine Derivatives / Q000009:adverse effects / Q000627:therapeutic use; D016540:Smoking Cessation; D000069447:Tiotropium Bromide; D014221:Triamcinolone / Q000627:therapeutic use
D000305:Adrenal Cortex Hormones; D000730:Androstadienes; D001993:Bronchodilator Agents; D012602:Scopolamine Derivatives; D014221:Triamcinolone; D019819:Budesonide; D000068299:Salmeterol Xinafoate; D000068298:Fluticasone; D009241:Ipratropium; D000420:Albuterol; D011241:Prednisone; D000069447:Tiotropium Bromide