Background - Patients with chronic disease comply with about 50% of th
eir treatment. The complex and time consuming daily drug regimens need
ed in the care of adult patients with cystic fibrosis encourage non-co
mpliance with prescribed treatments. Understanding the reasons for, an
d the extent of, non-compliance is essential for a realistic appraisal
of the patient's condition and sensible planning of future treatment
programmes. Methods - Patients were invited to complete a questionnair
e which asked about their compliance with daily treatment. The data we
re used to calculate a compliance score, the percentage of prescribed
treatment taken, and to examine patient attitudes to each individual p
rescription. An assessment score derived from consultant, cystic fibro
sis research fellow, specialist nurse, and physiotherapist ratings of
patient compliance was compared with the compliance score. Both scores
were correlated with patient characteristics and disease severity, an
d the compliance score was also correlated with the patient's knowledg
e of cystic fibrosis. Results - More than half the patients claimed to
take more than 80% of their treatments. Compliance with individual tr
eatments varied according to their perceived unpleasantness and degree
of infringement on daily activities. The most common reason given for
omitting treatment was forgetfulness. Professional carers were poor j
udges of patient compliance. There was no correlation between complian
ce and patients' sociodemographic characteristics or their knowledge a
bout cystic fibrosis. Conclusions - Non-compliance is universal and sh
ould be recognised as normal behaviour. There are no reliable criteria
for predicting any patient's level of compliance. Treatment protocols
should be planned around individual patient's requirements, modifying
treatment ideals where necessary according to the exigency and patter
n of that patient's lifestyle.