Medicare and Pre-existing Conditions – Will I Be Affected?

Grandparents pre-existing conditions

You might be wondering how your pre-existing conditions, like diabetes or hearing loss, may affect your Medicare coverage. Well, we have good news for you! Original Medicare (Part A and Part B) will cover your pre-existing conditions as long as you’re eligible for Medicare and enrolled. Medicare Part D (Prescription Drug Plan) will also cover you regardless of your pre-existing conditions, current prescriptions, or your medical history. Additionally, both Medicare Advantage and Medicare Supplement Insurance (Medigap) plans typically offer coverage for pre-existing conditions, but there may be limitations for each plan.

What are pre-existing conditions?

Pre-existing conditions are health conditions that you had before the start date of your new health care coverage. You have “guaranteed issue rights” with Medicare. This means all plans must cover you for pre-existing conditions as long as you enroll when you’re first eligible for Medicare. If you miss this initial enrollment period, your Medicare coverage may be affected by pre-existing conditions. It all depends on the plan.

Original Medicare and pre-existing conditions

Medicare Part A and Part B cover pre-existing conditions. Medicare Part A provides coverage for inpatient care, inpatient nursing care and inpatient services. Medicare Part B includes health care coverage for doctors’ services, outpatient care and preventative services. Plus, if your doctor accepts Medicare, you may be able to keep seeing them.

You may even be able to enroll in Original Medicare before you’re 65 if you have certain health conditions. This can apply to you, if:1

  • You’re already receiving benefits from the Social Security Administration (SSA) or Railroad Retirement Board (RRB): This applies if you’ve been receiving these benefits for 24 months. On the 25th month, you’ll be automatically enrolled in Medicare.
  • You have ALS: You’ll be automatically enrolled in Medicare Part A and Part B when your disability benefits start to kick in.
  • You have end-stage renal disease (ESRD): You can enroll in Original Medicare. Coverage usually starts on the first day of the 4th month of your dialysis treatments.

Medicare Part D (prescription drug) coverage and pre-existing conditions

Medicare Part D covers you regardless of pre-existing conditions as long as you’re enrolled in Medicare Part A and Part B (Original Medicare). Medicare Part D plans can’t deny you coverage based on your medical history, or because of what prescription drugs you’re taking. However, Medicare Part D is not included in Original Medicare. You have to enroll separately.

Medicare Advantage and pre-existing conditions

Medicare Advantage covers the same services as Medicare Part A and Part B, plus added benefits like vision, dental and prescription drugs. Medicare Advantage plans typically can’t deny you coverage, but there are special cases. You won’t be able to enroll in some Medicare Advantage plans if you have end-stage renal disease (ESRD).2

If you do have a chronic, pre-existing condition like ESRD, you may be able to enroll in a Medicare Advantage Special Needs Plans (SNP). You may qualify if you have:

  • Alcoholism
  • Drug addiction
  • Autoimmune disorder
  • Cancer
  • End-stage renal disease
  • Dementia

However, this is not the full list of qualifications for an SNP plan. You can contact your chosen Medicare plan provider for more information.

Medicare Supplement Insurance and pre-existing conditions

The best time to apply in a Medicare Supplement Insurance plan is during your Open Enrollment Period (OEP) for this plan. The OEP for Medicare Supplement Insurance is the 6-month period after the first month you’re 65 and have Medicare Part B health care coverage. If you apply during this window, your Medigap plan can’t deny you health care coverage. If you apply outside of your open enrollment period, you may have to go through additional steps to get coverage:

  • The plan could choose to underwrite your application. Simply put, this means that they’ll look at your application in closer detail. Underwriters typically look at information around your medical background, family’s health history, and your current lifestyle. Depending on their findings, there’s a chance your application could be denied.
  • If you have a pre-existing condition, the Medigap plan can deny your application or postpone your coverage for the first 6 months of your policy.

What is the open enrollment period for Medicare?

When you’re enrolling in Medicare or are considering changing plans, there are four main enrollment periods to keep in mind.3

The four main Medicare enrollment periods

There’s a lot to learn when it comes to Medicare, including how to make sure all of your health needs, like pre-existing conditions, are covered under your plan.

Initial Enrollment Period Open Enrollment Period
The initial enrollment period is when you’re first eligible to enroll in Medicare. This period is three months before your 65th birthday and continues for three months after.
This enrollment period applies to everyone. If you miss your initial enrollment period, you may have to pay a late fee or penalty. However, you’ll get the chance to enroll in Original Medicare again during the General Enrollment Period.
This applies to those who want to switch to Medicare Advantage or add Medicare Part D coverage. The open enrollment period is each year, from October 15 to December 7. If you enroll in a plan during this time, your new coverage will start January 1 the following year.
For Medicare Supplement Insurance plans: This 6-month period starts the first month you’re 65 and have Medicare Part B coverage. Your initial open enrollment period is usually the only time you can apply without answering health questions.
General Enrollment Period Special Enrollment Period
This applies to those who missed the open enrollment period or initial enrollment period for Medicare Part A and Part B. The General Enrollment Period is January 1 through March 31 every year. If you enroll during this timeframe, your coverage starts July 1 of that year. There are special enrollment periods (SEPs) for Medicare Part A and Part B, as well as for Medicare Advantage and Part D (prescription drug plan). If you’re turning 65 but already have health care through your employer or spouse’s employer or union health group, this enrollment period may apply to you when/if you enroll in these Medicare plans.

SOURCES: Web page; How do I get Parts A & B? Retrieved on February 7, 2019, from

2 Medicare Interactive. Web page; Medigaps and Prior Conditions. Retrieved on July 26, 2018, from

3 Web page: Things to Know about Medicare Advantage Plans. Retrieved July 26, 2018, from