Data on the importance of the delay between onset of symptoms and registrat
ion as a risk factor for impairment are sparse. This study investigates the
quantitative relationship between this delay, other risk factors and the i
mpairment status in new leprosy patients. It reports on 592 new leprosy pat
ients enrolled in 1988-1992 in the prospective ALERT MDT Field Evaluation S
tudy in central Ethiopia (AMFES). The influence of the risk factors sex, ag
e, delay, PB/MB classification in relation to BI, and prior dapsone treatme
nt on the impairment status at intake is analysed. Estimates for the delay
are based on patient recall. For the risk factors, odds ratios on impairmen
t and on severity of impairment were calculated using both univariate and m
ultivariate logistic regression. The registration delay was 2 years or more
for 44% of new patients. The prevalence of impairment (WHO impairment grad
es 1 and 2 combined) increased continuously from 36% for new patients with
a delay of 0-1 year to 81% for new patients with delays of 4 years or more.
This prevalence also increased continuously with age; it rose from 26% in
children to 80% for the age group 60 and over. In the multivariate regressi
on, the odds ratios for new patients to be impaired were statistically sign
ificant for all delay categories (baseline 1-2 years) and age groups (basel
ine 15-29 years). No statistically significant differences in odds ratios w
ere observed with respect to sex and PB/MB classification in relation to BI
. Overall, 31% of new patients presented with WHO impairment grade 1 and 23
% with grade 2. The risk on grade 2 also increased with the registration de
lay amongst the impaired new patients. Relatively few impaired males and re
latively few impaired MB patients with a BI value of 3 or higher had grade
2 impairment. Registration delay and age are the main risk factors for pres
entation with impairment. Reduction of delay in central Ethiopia requires r
e-thinking of control methodologies. The search for ways to reduce delays i
n diagnosis and treatment should receive high priority in leprosy research
and in leprosy control programmes.