Future prevalence of WHO grade 2 impairment in relation to incidence trends in leprosy: an exploration.
OBJECTIVE
To explore the relationship between leprosy incidence trends and the future prevalence of World Health Organization (WHO) grade 2 impairment caused by leprosy.


METHODS
Three scenarios were defined to estimate incidences and prevalences of leprosy impairment beyond 2000, assuming 6%, 12% and 18% annual declines in case detection rate respectively, and 6% impairment among new patients. Case detection data from 1985 to 2000 were used for projecting leprosy incidences up to 2020. To estimate future prevalences of WHO grade 2 impairment, the survival of existing and new impaired individuals was calculated.


RESULTS
In the 6% scenario, 410 000 new patients will be detected in 2010 and 250 000 in 2020. The number of people living with WHO grade 2 impairment in these years will be 1.3 and 1.1 million, respectively. The 12% scenario predicts that 210 000 new patients will be detected in 2010 and 70 000 in 2020. The grade 2 prevalences will be 1.2 and 0.9 million, respectively. In the 18% scenario, the incidence will be 110 000 in 2010 and 20 000 in 2020, and the grade 2 prevalences will be 1.1 and 0.8 million, respectively.


CONCLUSIONS
Declines in numbers of people living with grade 2 impairment lag behind trends in leprosy incidence. The prevalence of people with grade 2 decreases much slower than leprosy incidence and case detection in all three scenarios. This implies that a substantial number of people will live with impairment and will need support, training in self-care and other prevention of disability interventions in the next decades.
Meima
Abraham
A
Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
van Veen
Natasja H J
NH
Richardus
Jan H
JH
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004185:Disability Evaluation; D006233:Persons with Disabilities / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007918:Leprosy / Q000150:complications* / Q000453:epidemiology* / Q000401:mortality; D008875:Middle Aged; D015995:Prevalence; D012720:Severity of Illness Index; D016019:Survival Analysis; D014944:World Health Organization