Abstract
Purpose :
To use national glaucoma medication unit sales data correlated with age adjusted population based primary glaucoma prevalence data from 5 population based studies from India to estimate the proportion of untreated glaucoma in India from 2008-2016.
Methods :
We estimated the number of persons aged 40 and above with primary glaucoma in India from age stratified glaucoma prevalence reported by 5 population based studies from India. The estimates were weighted for sample size in each age cohort and the number of persons estimated to have disease was calculated from the estimated population for each year between 2008 and 2016. The annual glaucoma unit sales information was obtained from the Indian market survey data for the years 2008-2016. To derive the proportion of medically treated glaucoma we used two models : Model 1- 12 units/ year irrespective of the use of combination/single drug and Model 2 -16.44 units/year was derived from published glaucoma medication prescription patterns in India(1.37 drugs/month/patient), accounted for the number of glaucoma medications in the vial.
Results :
The population estimates for primary glaucoma in 2008 was 8.3 million, this increased to 10.7 million by 2016. For glaucoma drug unit sales these were 10.1 million for 2008 and 19.9 million for 2016. The estimated proportion of persons with primary glaucoma who were using glaucoma medications for these time points was 10.1% and 15.4% for Model 1 ( 1 vial /month) and 7.98% to 12.43% for Model 2 (1.37 vials per month). These figures are in good agreement with the proportion of untreated disease reported in the 5 studies. The changes in numbers over 8 years were, for those with primary glaucoma: 28.9%, drug sales: 97%, treated proportion model 1: 52.4% and Model 2: 55.7%.
Conclusions :
We describe a novel approach to estimate the proportion of untreated primary glaucoma in in India. In spite of huge increases in glaucoma drug sales, changes in the numbers of those with detected disease have been modest because of the population distribution of the country. Inspire of a doubling of drug sales the treated proportion is still only 15% of the glaucoma population and there is an urgent need to improve glaucoma detection rates to limit glaucoma related visual morbidity.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.