Top Outpatient Diagnoses by ICD-10 Code

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The industry-wide shift from inpatient to outpatient care is well documented by healthcare providers (HCPs) and industry experts. Advancements in hospital technology and treatments are enabling a greater number of patients to seek effective care without being admitted. This trend is helping to lower overall care costs, improve patient outcomes, and reduce unnecessary admissions. According to our hospital financial data, outpatient treatment accounted for nearly 57 percent of hospital net patient revenue in 2017.

In the first half of 2018, outpatient visits were dominated by preventative care measures such as immunizations, cancer screenings, and other preliminary examinations.

Top 10 Outpatient Diagnoses at Hospitals by Volume, 2018

Rank ICD-10 Code Description Number of Diagnoses
1. Z1231 Screening mammogram for malignant neoplasm of breast 7,875,119
2. I10 Essential (primary) hypertension 5,405,727
3. Z23 Immunization 3,219,586
4. Z0000 General adult medical examination without abnormal findings 3,132,463
5. E119 Type 2 diabetes mellitus without complications 2,869,831
6. N390 Urinary tract infection, site not specified 2,502,306
7. M545 Low back pain 2,350,906
8. J069 Acute upper respiratory infection, unspecified 2,293,088
9. Z01818 Encounter for other preprocedural examination 2,116,159
10. Z79899 Other long term (current) drug therapy 2,018,463

Fig 1 ICD-10 diagnosis data is from January through June 2018. Claims information retrieved from the 2018 Medicare Quarterly standard analytic files (SAF).

Preprocedural screenings and general examinations were the top outpatient treatments by volume in 2018, with a combined 5.2 million claims in the first half of the year. Mammograms are the top-reported outpatient claim, which indicates the emphasis providers place on cancer prevention and early detection. Many of the diagnoses above are becoming more common, as providers view services like vaccinations and primary care visits as relatively easy means to improve and maintain public health, which is tied to higher reimbursement rates and improved patient outcomes. This is similar with mammograms, which can be an effective way of detecting breast cancer early, saving lives and lowering care costs.

Management of chronic conditions also make up a significant portion of the most commonly reported diagnoses: hypertension, back pain, type 2 diabetes and long-term drug therapy are among the top 10. Hypertension and type 2 diabetes are common throughout the U.S., and chronic back pain is a symptom of various conditions, including ruptured disks, arthritis, and traumatic injuries.

In terms of diagnoses by payments, cancer screening and treatments took half of the top 10 spots. These are followed closely by heart-related events such as chest pain and heart disease. This is unsurprising considering the high cost of oncology drugs and other treatments, as well as the prevalence of heart disease in the U.S.

Top 10 Outpatient Diagnoses at Hospitals by Total Payments, 2018

Rank ICD-10 Code Description Total Payments
1. Z5111 Antineoplastic chemotherapy $6,632,833,304
2. Z5112 Antineoplastic immunotherapy $3,903,554,289
3. R079 Chest pain, unspecified $1,607,973,745
4. R0789 Other chest pain $1,529,268,426
5. Z1211 Screening for malignant neoplasm of colon $1,452,502,044
6. Z510 Antineoplastic radiation therapy $1,396,256,897
7. I2510 Atherosclerotic heart disease of native coronary artery without angina pectoris $1,356,208,677
8. Z1231 Screening mammogram for malignant neoplasm of breast $1,095,419,467
9. G35 Multiple sclerosis $988,933,070
10. R55 Syncope and collapse $918,812,416

Fig 2 ICD-10 diagnosis data is from January through June 2018. Claims information retrieved from the 2018 Medicare Quarterly standard analytic files (SAF).

Antineoplastic chemotherapy is the top outpatient diagnosis by total payments for the third time since 2015. In the first half of 2018 alone, payments totaled more than $6.6 billion — an increase of nearly 25 percent from the same time period in 2015. Both "chest pain, unspecified" and "other chest pain" saw an increase in total payments in the last 3 years, moving from spots 6 and 10 to spots 3 and 4, respectively. Colon screening payments increased from about $800 million in 2015 to over $1.4 billion during the same period in 2018, rising from the 9th spot to the 5th.

In the tables above, the top ICD-10 codes represent outpatient diagnoses at hospitals, not physician practices. Hospitals generally have higher costs associated with treatment of chronic illnesses than physician practices and other care centers, and therefore may receive higher reimbursement rates — though the federal government is looking to decrease hospital payments over the next 10 years.

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