ED Coding and Reimbursement Alert

Question: What is the difference between essential (primary) hypertension and secondary hypertension, and how do I choose ICD-10 codes for each condition?

Missouri Subscriber

Answer: To put it plainly, primary hypertension isn’t caused by an underlying condition. Secondary hypertension is caused by an identifiable underlying condition. Also, coding for secondary hypertension is more involved.

• Primary hypertension: Report this condition with I10 (Essential (primary) hypertension).
• Secondary hypertension: You’ll need to start at I15.- (Secondary hypertension)
• I15.0 (Renovascular hypertension)
• I15.1 (Hypertension secondary to other renal disorders)
• I15.2 (Hypertension secondary to endocrine disorders)
• I15.8 (Other secondary hypertension)
• I15.9 (Secondary hypertension, unspecified)

Code also: ICD-10 has a code also note under I15.- to “Code also underlying condition.” Be sure to submit an ICD-10 code for the condition that’s causing the secondary hypertension to your claim. Conditions that can cause secondary hypertension include:

• Chronic kidney disease (CKD)
• Renal artery stenosis
• Glomerulonephritis
• Primary hyperaldosteronism (Conn’s syndrome)
• Cushing’s syndrome
• Hyperthyroidism and
• Hypothyroidism
• Coarctation of the aorta
• Obstructive sleep apnea (OSA)
• Hypercalcemia
• Medication-induced hypertension.