RT Journal Article SR Electronic T1 A characterisation of patient drop outs in a cohort of HIV positive homosexual/bisexual men and intravenous drug users JF Journal of Epidemiology and Community Health JO J Epidemiol Community Health FD BMJ Publishing Group Ltd SP 66 OP 67 DO 10.1136/jech.55.1.66 VO 55 IS 1 A1 W K Poole A1 R Perritt A1 K B Shah A1 Y Lou A1 J Turner A1 P Kvale A1 P C Hopewell A1 J Glassroth A1 M Rosen A1 L Reichman A1 J Wallace A1 the Pulmonary Complications of Immunodeficiency Virus Infection Study Group YR 2001 UL http://jech.bmj.com/content/55/1/66.abstract AB