Thanks for your valuable comments. Basically we were searching for some matching tool between ICPC and ICD. The link that you have shared with me, shows that the ICPC and ICD matched document is available with WHO. So, we would collect it for our study.
However, in our secondary level data on morbidity and health expenditure, there is no clear information available on co-morbidity. So, we are searching for some robust data/methodology to capture the extent of co-morbidity and the related health expenditure in India.
There are some efforts on that, initiated by the WHO in the past decade and Jacob Mazalale suggestion is very good. You must need to explore the WHO sites because many things have been produced there. I participated in the production of the reproductive health accounts (I am attaching it). Other efforts had been done in other diseases. This effort is going slow because it needs a lot of data from public and private sector and most countries accounts are not organized by disease expenditures. But it is an essential area for future planning of the sector. Good luck in your research.