Intensity of Imaging for Low Back Pain in Elderly Patients AcademyHealth Annual Meeting June 2007 HH Pham, MD, MPH, D Schrag, MD, MPH C Corey, MS, J Reschovsky, PhD HR Rubin, MD, PhD, BE Landon, MD, MBA

Background  Medicare spending on imaging services has increased dramatically since 2000 with unclear clinical benefits for beneficiaries  Guidelines allow discretion for imaging of elderly patients with acute low back pain  Little representative data on non-clinical factors associated with intensity of imaging

Research questions What physician, practice, market, and non- clinical patient factors are associated with more intensive imaging for acute low back pain?  Does the economic environment in which physicians practice influence discretionary use of imaging?

Data sources (1) Community Tracking Study Physician Survey Nationally representative, clustered in 60 communities Non-federal, completed training, 20+ hrs of clinical care/week 12,406 respondents, ~50% PCPs 59% response rate Questions Specialty, board certification, FMG status Practice type, revenue sources (Medicaid, Medicare), capitation Ability to obtain specialist and imaging referrals Overall effect of financial incentives (increase/decrease services) Compensation based on quality, profiling, patient satisfaction Practice ownership

Data sources (2) Complete Medicare claims for 1.09 million beneficiaries seen by CTS physicians in year 2000 Geographic data from Area Resources File on number of patient care radiologists per capita, household income, and education levels

Design and Analysis  Back pain diagnosis identified for year 2001  Followed for 6 months after back pain diagnosis  Modeled “intensity” of imaging never imaged  imaged days  imaged within 28 days “Intensity” measured for: - (a) any imaging modality; and (b) only CT/MRI  Excluded patients diagnosed by a radiologist  Adjusted for comorbidities during year 2000, physician, practice, and area factors (site fixed effects)  Repeated analyses, excluding patients with visits to other physicians between diagnosis and imaging dates

63,075 (15%) patients of 318,148 linked to a CTS PCP and had a diagnosis of acute low back pain in ,515 (39%) meeting clinical inclusion criteria (no potential indications for imaging 6 months prior to LBP diagnosis or between diagnosis and imaging dates 5,964 (28%) imaged within 28 days  5,330 (90%) by XR  725 (12%) by CT/MRI 15,011 (67%) never imaged 1,017 (4%) imaged between days  734 (73%) by XR  314 (31%) by CT/MRI 21,992 (89%) meeting inclusion criteria and not diagnosed by a radiologist Study population

Clinical exclusions Modified NCQA’s measure of inappropriate imaging for acute LBP  Cancers*  Neurologic deficits*  Trauma,* falls, injury  Infections – endocarditis, osteomyelitis, TB, etc.  IV drug use*  Anemia – not hereditary, Fe deficiency, or blood loss  Constitutional symptoms – weight loss, fever, night sweats, fatigue/malaise, loss of appetite

Care relationships between acute LBP patients and their plurality PCP Median (IQR) % of E&M visits with PCP63 (47-80) Had a visit with their CTS PCP within 6 months of LBP diagnosis 81% Diagnosed by their CTS PCP52% Diagnosed in their CTS PCP’s practice60% Diagnosed by any PCP Specialties of other diagnosing clinicians (outside of their CTS PCP’s practice) 62% Orthopedic surgeon9% Chiropractor15%

Site of imaging studies performed within 28 days of diagnosis Modality Total imaged N Patients imaged in PCP’s practice N (%) Any6,9812,439 (37.5) X-Ray6,0642,192 (38.9) CT or MRI1, (27.1)

Timing of imaging after LBP diagnosis Imaging procedure Patients, N Number of days between diagnosis and imaging, Median (IQR) Any modality6,9810 (0-7) CT1659 (3-35) MRI87913 (4-36)

Predictors of intensity of imaging Patient factors and radiologist supply Characteristic Any modality Adjusted OR (95% CI) CT or MRI Adjusted OR (95% CI) Female1.01 ( )0.81 ( )* Medicaid eligible0.81 ( )*0.94 ( ) Race (vs. white) Black0.83 ( )*0.67 ( )* Other0.95 ( )0.91 ( ) Radiologists/1000 (vs. lowest quartile) Highest quartile1.10 ( )1.31 ( )* No effect for median household income in the patient zip code; % adults with 12+ yrs of education in the county; or Klabunde or Charlson scores

Predictors of intensity of imaging Physician factors Characteristic Any modality Adjusted OR (95% CI) CT or MRI Adjusted OR (95% CI) FP/GP specialty (vs. IM)0.95 ( )0.83 ( ) Effect of incentives (vs. increase services) To reduce services0.83 ( )0.73 ( )* No effect on services1.03 ( )1.00 ( ) No effect for years in practice; board certification; IMG status; compensation based on productivity, quality, profiling or patient satisfaction measures, or practice ownership

Predictors of intensity of imaging Practice factors Characteristic Any modality Adjusted OR (95% CI) CT or MRI Adjusted OR (95% CI) % Revenue from capitation (vs. none) 1-10%1.05 ( )0.84 ( ) 11-25%0.98 ( )0.74 ( )* >25%0.94 ( )0.67 ( )** Practice type (vs. solo/2) Small group (3-10)1.19 ( )*1.10 ( ) Medium group (11-50)1.49 ( )***0.94 ( ) Large group (>50)1.22 ( )*1.29 ( ) Medical school0.84 ( )0.64 ( ) No consistent effect for revenue from managed care, Medicare, or Medicaid

Limitations No certainty regarding appropriateness of imaging Not benchmarking – only comparing relative performance Unlikely systematic under-coding of exclusions by physician or practice characteristics, or by white patient race and higher SES Uncertainty is comparable to claims-based measures of underuse Lack data on presence of imaging equipment in practices Cannot identify physician(s) responsible for referrals For imaging or to specialists But consistent relationships between characteristics of the CTS PCP and intensity of imaging

Conclusions  Substantial minority of elderly patients with uncomplicated LBP are imaged early, often in their physician’s practice Most cases of rapid imaging use XR’s, not CT/MRI  Overall financial incentives matter, but no association with specific types of performance-based compensation  Subgroups of patients who tend to receive fewer services may sometimes benefit  Incentives to increase or decrease services may have mixed effects on quality that may go undetected if the majority of performance metrics reflect underuse

Geographic variation in percent of patients imaged within 28 days Before exclusions After clinical exclusions Any Modality After clinical exclusions CT/MRI CTS MarketUnadjusted % Adjusted %Unadjusted %Adjusted % Seattle Phoenix Miami Newark Cleveland Indianapolis Lansing Greenville Little Rock Orange Cty Boston Syracuse