OUR METHODOLOGY

Overuse (also known in the clinical community as low-value care) is the delivery of healthcare services that are more likely to harm than benefit the patient. The component comprises overuse rates of 12 common low-value tests and procedures, chosen based on their validation in previous research on measuring overuse. Hospitals’ overuse score for each service is based on the rate of overuse as well as the volume of overuse. For the overuse composite ranking, more weight placed on the services that make up the larger share of overuse.

To create this metric, we used Medicare claims data from January 1, 2019 – December 31, 2022. We included Medicare fee-for-service claims for 2020-2022 and Medicare Advantage claims for 2019-2021, the most recent time periods available.

For Acute Care Hospitals, we ranked hospitals on all 12 services (see below). Acute Care Hospitals with data available for six or more services were ranked on avoiding overuse. Critical Access Hospitals were ranked on carotid artery imaging for fainting and head imaging for fainting, as these services had adequate volume for most critical access hospitals. Critical Access hospitals with data for both of these services were given an avoiding overuse ranking.

Low-value tests and services:

Arthroscopic knee surgery – Surgery to remove damaged cartilage or bone in the knee using an arthroscope (tiny camera). Defined as overuse for patients with osteoarthritis or “runner’s knee” (damaged cartilage). Excluding patients with meniscal tears. Only Acute Care hospitals are ranked on this measure.

Carotid artery imaging for fainting – A test to screen for carotid (neck) artery disease. Considered overuse for patients where syncope (fainting) is the primary diagnosis, and there is no history of syncope in the past two years. Excluding patients with stroke or mini-stroke, retinal vascular occlusion/ischemia, or nervous and musculoskeletal symptoms. Both critical access and Acute Care hospitals are ranked on this measure.

Carotid endarterectomy – Procedure to remove plaque buildup from a carotid (neck) artery in a patient to prevent stroke. Considered overuse when performed on female patients without stroke symptoms or history of stroke. Only Acute Care hospitals are ranked on this measure.

Colonoscopy screening – Test for asymptomatic colorectal cancer. Defined as overuse for patients over 85 years old or performed more than once in a nine year period. Excluding patients with symptoms of colorectal cancer and patients at high risk of colorectal cancer. Only Acute Care hospitals are ranked on this measure.

Coronary artery stenting – Also known as percutaneous coronary intervention. Procedure to place a stent or balloon in a coronary artery using a catheter. Also includes procedures where the artery is opened but a stent is not inserted. Defined as overuse when performed on patients with stable heart disease (not having a heart attack or unstable angina). Excluding patients with past diagnosis of unstable angina. Only Acute Care hospitals are ranked on this measure.

EEG for fainting – A test of the electrical activity of the brain. Considered overuse for patients where syncope (fainting) is the primary diagnosis, and there is no history of syncope in the past two years. Only Acute Care hospitals are ranked on this measure.

EEG for headache – A test of the electrical activity of the brain. Defined as overuse for patients with headache as the primary diagnosis on the claim and no history of headache in the past two years. Excluding patients with epilepsy and recurrent seizures, convulsions, and abnormal involuntary movements. Only Acute Care hospitals are ranked on this measure.

Head imaging for fainting – Considered overuse for patients where syncope (fainting) is the primary diagnosis, and there is no history of syncope in the past two years. Excluding patients with epilepsy or convulsions, cerebrovascular diseases, head or face trauma, altered mental status, nervous and musculoskeletal system symptoms, and history of stroke. Both Critical Access and Acute Care hospitals are ranked on this measure.

Inferior Vena Cava (IVC) filter – Procedure to place a filter (a medical device) in the large vein in the abdomen to prevent blood clots from moving to the lungs. Considered overuse for all patients except those with history of multiple pulmonary embolism. Only Acute Care hospitals are ranked on this measure.

Renal artery stenting – Procedure to place a stent or balloon in the renal (kidney) artery. Considered overuse for patients with high blood pressure or plaque buildup in the artery. Excluding patients that had diagnosis of fibromuscular dysplasia of the renal artery (abnormal twisting of the blood vessels). Only Acute Care hospitals are ranked on this measure.

Spinal fusion/laminectomy – Procedure to fuse vertebrae together (spinal fusion) or remove part of a vertebra (laminectomy). Defined as overuse for patients with low-back pain, excluding patients with radicular symptoms, trauma, herniated disc, discitis, spondylosis, myelopathy, radiculopathy, radicular pain or scoliosis. Only Acute Care hospitals are ranked on this measure.

Vertebroplasty – Procedure to inject cement into the vertebrae to relieve pain from spinal fractures. Considered overuse for patients with spinal fractures caused by osteoporosis. Excluding patients with bone cancer, myeloma, or hemangioma. Only Acute Care hospitals are ranked on this measure.

The cost efficiency metric is a ratio of hospitals’ mortality rates compared to their Medicare costs. Hospitals with the lowest mortality and the lowest costs received the best scores in cost efficiency. Cost efficiency is comprised of two details, 30-day cost efficiency and 90-day cost efficiency, which are weighed equally to create the composite ranking.

For mortality, we used hospitals’ risk-standardized 30- and 90-day mortality for Medicare patients hospitalized between 2020 and 2022. For cost, we used 30- and 90-day total risk-standardized Medicare payments for patients hospitalized in 2020 to 2022. Payments were standardized for hospital patient risk (the conditions that hospital patients have as well as the procedures they received), so that hospitals with sicker patients were not punished for spending more to treat them. Payments were also adjusted for patient survival so that hospitals with low patient survival did not have artificially lower costs. Lastly, payments were adjusted for Medicare's regional cost differences, so that hospitals that get paid more by Medicare because of regional differences did not appear to have higher costs.

For each hospitalization, we found the claim payment amount in all claims within 30 or 90 days from the admission date. These claims included: inpatient, outpatient, carrier, skilled nursing facility, home health agencies, durable medical equipment, and hospice claims. We excluded any claims where Medicare denied the payment. Transfers were excluded. Hospitalizations with probable or confirmed COVID-19 were excluded.

Medicare adjusts its payment amounts to hospitals and other providers based on various geographic factors. To account for this, we calculated standardized payments using the Virtual Research Data Center’s public use files of 2019 to 2021 Hospital Referral Regions (HRR) standardized ratio tables for patients over 65. As the 2022 data was not available, we re-used 2021 HRR estimates for 2022 claims.

Our goal for the cost efficiency score was to reward hospitals with low mortality rates and low costs and give the lowest scores to hospitals with high mortality rates and high costs. We also decided to bias our scores to give hospitals with high costs and low mortality a higher score than hospitals with low costs and high mortality. This is because we believe that if there is a trade-off between costs and mortality, we should favor better mortality rates compared to lower costs.

The clinical outcomes component measures how well the hospital keeps patients alive and prevents return trips to the hospital, over various periods of time. All of the measurement and results for Acute Care and Critical Access Hospitals was performed separately on the split populations. For mortality and readmissions metrics, hospitalizations with probable or confirmed COVID-19 were excluded.

Using Medicare claims, we evaluated hospital clinical outcomes based on mortality and readmissions. We included Medicare fee-for-service claims for 2020-2022 and Medicare Advantage claims for 2019-2021, the most recent time periods available. The clinical outcomes metric is composed of risk-standardized rates of mortality and readmission, weighted at 80% and 20% respectively.

Mortality included rates of in-hospital, 30-day, and 90-day mortality. We chose these mortality endpoints to cover measurements in CMS' inpatient quality reporting programs as well as more extended periods when mortality is a function of both hospital and community. We also included risk-standardized rates of 7- and 30-day readmission, to include both a shorter interval that would reflect inpatient care quality, and longer follow-up that would reflect post-hospital community support.

New to the Lown Index in 2024 is unplanned hospital visits post outpatient surgery within 7 days, which includes inpatient admissions directly following surgery as well as any ED visit, observation stay, or unplanned inpatient admission following discharge from the hospital outpatient department (defined using CMS’s unplanned admission algorithm). We do not report unplanned hospital visits post outpatient surgery for Critical Access Hospitals, as the majority of these hospitals do not have high outpatient volumes.

Mortality, readmissions, and unplanned hospital visit rates rates were risk adjusted using the Risk Stratification Index (RSI), a Lown Institute-specific version of a machine-learning algorithm in the public domain that has been validated on multiple national, state-based, and hospital-based datasets. RSI has been shown to predict outcomes with greater discriminatory accuracy compared with other publicly available risk adjustment tools, by adjusting outcomes for numerous patient conditions and procedures. This allows us to better compare outcomes across patients that have the same medical needs. In addition to the patient conditions in RSI, we accounted for differences in hospital volume, patient risk, Medicare/Medicaid dual-eligibility rates, and types of services performed.

The patient safety component measures how well hospitals avoid preventable patient safety errors. We used well-established indicators provided by CMS on its Care Compare website for hospitalizations--such as rates of pressure ulcers, accidental punctures, and central intravenous line infections--for hospital admissions in 2020-2023.

We included the CMS composite measure (PSI-90) from January 2020 to March 2023, which comprises 10 separate indicators of patient safety. We used five hospital-acquired infection (HAI) measures from CMS. We included a reliability adjustment for the HAI measures using the reported numerator and denominator counts from Care Compare. For a patient safety overall score, hospitals had to have had at least three of the PSI-90 or HAI results.

The six detailed metrics (PSI-90 composite and five HAI measures) were weighted equally to formulate the overall patient safety component score. Like CMS, we excluded Critical Access hospitals from this metric due to a lack of available data.

The patient satisfaction component measures aspects of the hospital experience as reported by patients. For this component, we used CMS's annual Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey from April 2022 to March 2023 to give a rating of patient experience across 10 factors, including hospital quietness, cleanliness, healthcare staff responsiveness, and communication. We took the average of the 10 linear mean scores of these factors published on the 2024 Care Compare site. As with all Lown Index measures in 2024 and onward, Acute Care and Critical Access hospital rankings were separate so each type of hospital was compared to their peers.

Care Compare did not report scores for hospitals that had fewer than 100 responses. We chose to include hospitals with between 50 and 100 responses after data analysis indicated that the imputation of these scores would be reasonable to account for CMS’s mean calculations and adjustment. We calculated scores for these hospitals by extrapolating to the nearest median score of hospitals with similar survey responses.

Care Compare did not report scores for hospitals that had fewer than 100 responses. We chose to include hospitals with between 50 and 100 responses after data analysis indicated that the imputation of these scores would be reasonable to account for CMS’s mean calculations and adjustment. We calculated scores for these hospitals by extrapolating to the nearest median score of hospitals with similar survey responses.