"If you think a medical rider works differently in terms of renewal, think again. Although medical rider is attached to an ILP, your medical card policy renewal is subject to insurance company discretion too, based on the factors mentioned above."

FYI, I see a premium increase of 20% even though I NEVER made any medical claim under me and my kids life+investment+medical link insurance.
The bottom line, buy it for a peace of mind and as long as you can afford it.
Cause in the end of the day, the insurance company will find ANY reason to increase your premium.

1. Please don't rely on ringgitplus for insurance information. Seriously, no. Kinda unread what you have read.

2. When you buy from medical be it standalone or ILP, most of them do not impose additional loading when you claim. Why I say most? In the past some of the general insurer do have this terms and conditions where they can do so. Add loading or dont renew. However this is somewhat outdated. Also, even this is somewhat hearsay that I picked up. I can't fully verify. But if you open website of few famous brands (not general insurance) you will realise don't have these terms and conditions where they can suddenly don't offer, etc... 

Caveat, however, recently, one company, launch a new medical product (it's a rider). Basically the concept they use is similar to your car insurance punya NCD. If you don't claim, you get discount. If you claim, you pay more. If you claim even higher amount, you pay even more. So it does cut both ways.

3. Due to complexity of how insurance works, most people tend to not understand what is going on because it is complicated  I have seen people in the industry, agents misunderstand, so not specific to you. In the case of your parents, it could be due to both old age and repricing effect that resulted in that 75% increase. Normal customer tak tau, ingat naik harga sebab claim (confirmation bias). Sebenarnya, medical revision. Anyway, this is just my educated guess, could be wrong.

4. Individual health circumstances matters when you purchase. After you purchase, provided you were truthful, insurance companies don't suddenly penalise you.

While no source, again hearsay, BNM kinda soft ban this. So, the insurance companies decline to renew you cause you claim a lot, etc...