The best replacement for comorbidity is dual diagnosis.

The best alternatives to comorbidity are rated as following:
★★★★★  dual diagnosis
★★★★  co-morbidity
★★★  multimorbidity
★  complication

Your alternative for comorbidity is not listed? Suggest!
Speaking about comorbidity, one probably shouldn't forget about adhd.

Other search terms related to comorbidity and their ratings are:
★★★★★ adhd
★★★ obesity
You have in mind a companion for comorbidity and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of comorbidity in all years. Click on graph for more.
comorbidity
dual diagnosis
co-morbidity