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Facility-Level Variation in Cardiac Dhruv Mahtta,1,2,3 Sarah T. Ahmed,1,2 Nishant R. Shah,4 David J. Ramsey,1,2 Test Use Among Patients With Diabetes: Julia M. Akeroyd,1,2 Khurram Nasir,5 Findings From the Veterans Affairs Ihab R. Hamzeh,6 Islam Y. Elgendy,7 Stephen W. Waldo,8 National Database Mouaz H. Al-Mallah,9 Hani Jneid,6,10 3,6 Diabetes Care 2020;43:e58–e60 | https://doi.org/10.2337/dc19-2160 Christie M. Ballantyne, Laura A. Petersen,1,2 and Salim S. Virani1,2,3,10

Cardiac stress testing in patients with treadmill test, stress , evaluate variation among patients with diabetes mellitus (DM) is a topic of much and SPECT/PET MPI (myocardial perfu- DM with and without ischemic debate (1,2). The clinical heterogeneity sion imaging [single photon emission disease (IHD). Lastly, geographic varia- and varied interpretation of atypical symp- computed tomography or positron emis- tionin stresstest usewasdepicted (Fig.1) toms in this population may lead to sig- sion tomography]). Facilities with ,10 using Federal Information Processing nificant variation in cardiac stress testing studies/year were excluded. Median risk Standards (FIPS) codes. The Michael E. with downstream implications in health ratio (MRR), a well-established measure DeBakey VA Medical Center granted in- care expenditure. We evaluated facility- of facility-level variation (3), was derived stitutional review board approval. level variation in cardiac stress test use by constructing multivariable hierarchi- Our study included 1,448,906 patients among patients with DM across the Vet- cal modified regression models adjusted with DM, who were predominantly white eransAffairs(VA)healthcaresystem. for patient clustering and modeled (65.1%) and male (96.3%) with high prev- We identified patients with DM aged patient characteristics as filter effects alence of (83.1%) and IHD $18 years with a primary care clinic visit within each facility and individual facil- (33.1%). The meanDCG-RRS was1.69.Un- during VA fiscal year 2014 at one of the ities as a random effect (4). Unadjusted adjusted facility-level rates of stress test- 130 VA facilities and associated clinics. and adjusted MRRs (adjustment for pa- ing ranged from 2.40 to 19.32 studies per Patient demographics and medical his- tient, provider, and facility-level varia- 100 patients with a mean 6 SD of 9.77 6 tory were identified using clinical data bles) were calculated for overall stress 3.39 studies per 100 patients. Unad- sources and ICD-9-CM codes. We calcu- testing and individual stress modalities. justed MRR for overall stress test use was lated diagnostic cost group relative risk MRR represents the likelihood of two 1.52 (95% CI 1.44–1.60), which decreased to score (DCG-RRS), a validated surrogate random facilities differing in stress test 1.38 (95% CI 1.32–1.43) after adjustment for overall illness burden. Facility-level use for two similar patients. For example, for patient-level variables (age, sex, race, cardiac stress test use was defined as the MRR of 1 corresponds to no facility-level hypertension, IHD, DCG-RRS, and use of number of stress tests performed per variation, whereas MRR of 1.5 would insulin) and 1.37 (95% CI 1.32–1.43) after facility per 100 patients with DM in suggest 50% variation in stress test further adjustment for provider and facility- the preceding 365 days. Stress testing usefor twofacilities withsimilar patients. level variables (percutaneous coronary modalities evaluated included exercise We conducted sensitivity analyses to intervention accessibility and number of OBSERVATIONS –

1Health Policy, Quality & Informatics Program, Michael E. DeBakey VA Medical Center Health Services Research & Development Center for Innovations, Houston, TX e-LETTERS 2Section of Health Services Research, Department of Medicine, Baylor College of Medicine, Houston, TX 3Section of Cardiovascular Research, Department of Medicine, Baylor College of Medicine, Houston, TX 4Department of Health Services, Policy, and Practice, Brown University School of Public Health, Providence, RI 5Division of Cardiovascular Medicine, Center for Outcomes & Research Evaluation, Yale School of Medicine and Yale New Haven Health, New Haven, CT 6Section of , Department of Medicine, Baylor College of Medicine, Houston, TX 7Division of Cardiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 8Division of Cardiology, Department of Medicine, Rocky Mountain Regional VA Medical Center, Aurora, CO 9Methodist DeBakey Heart & Vascular Center, Houston Methodist Hospital, Houston, TX 10Section of Cardiology, Michael E. DeBakey VA Medical Center, Houston, TX Corresponding author: Salim S. Virani, [email protected] Received 29 October 2019 and accepted 3 February 2020 © 2020 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at https://www.diabetesjournals.org/content/license. care.diabetesjournals.org Mahtta and Associates e59

Figure 1—Variation in cardiac stress test use rates among patients with diabetes by county across all VA health care facilities. Rates represent the number of stress tests performed per 100 patients with diabetes per county per year.

cardiology visits in preceding 12 months). about appropriate use criteria (5), simul- appropriateness of stress testing in order This indicates a 37% variation in the prob- taneous practice, or recent training in to improve quality of stress testing. ability of two similar patients with DM at a non-VA health care system (where two random facilities receiving a stress factors of financial incentives or “defensive ” test. Similar magnitude of variation was medicine may be at play). Underuse of Funding. S.S.V. was supported by a Department observed across various stress modalities: stress testing by facilities with low use rates, of Veterans Affairs Health Services Research & exercise treadmill test (MRRadjusted 1.50, secondary to constraints in facility-based Development Service Investigator-Initiated Grant 95% CI 1.42–1.57), stress echocardiogram resources or higher reliability on cardiac (IIR 16-072), an American Heart Association – Beginning Grant-in-Aid (14BGIA20460366), the (MRRadjusted 2.67, 95% CI 2.24 3.10), and computedtomographicangiography,may American Diabetes Association Clinical Science SPECT/PET MPI (MRRadjusted 1.44, 95% CI also result in significant variation. A and Epidemiology award (1-14-CE-44), and the 1.38–1.51). Sensitivity analyses among marked nationwide geographic variation Houston VA Health Services Research & Devel- patients with DM with or without IHD mayalsobeattributedtoinefficient allo- opment Center for Innovations grant (CIN13-413). revealed an adjusted variation in overall cation of health care resources resulting N.R.S.wassupportedbyanAgencyforHealthcare Research and Quality award (5K12HS022998). stress test use of 39% in both subgroups. in a supply-demand mismatch. Our results Support for VA/Centers for Medicare and Medicaid Fig. 1 shows interstate and intrastate from a large health care system serve as Services data was provided by the Department of facility-level variation in overall stress benchmark data for variation in stress Veterans Affairs, VA Health Services Research & test use. testing. Future studies are warranted to Development Service, VA Information Resource Our results suggest that despite ad- assess system-wide appropriateness of Center (project numbers SDR 02-237 and 98-004). The opinions expressed reflect those of the justment for a multitude of covariates, stress testing, assess patient-level symp- authors and not necessarily those of the De- significant residual variation in overall tom data, and conduct qualitative analyses partment of Veterans Affairs or the U.S. stress test use exists among veterans to understand individual provider-level government. with DM with or without IHD. Several drivers behind such variation. Duality of Interest. K.N. serves on the advisory factors may explain these findings. Clin- In conclusion, we demonstrated a 37% board of The Medicines Company and Regen- eron. S.W.W. receives investigator-initiated re- ical heterogeneity among patients with residual facility-level variation in stress search support to the Denver Research Institute DM and atypical or absent presenting test use. This level of unexplained var- from ABIOMED, Cardiovascular Systems Incor- symptoms creates a level of uncertainty iation across a nationwide health care porated, and Merck Pharmaceuticals. C.M.B. that may lead to substantial variation in system presents an opportunity for con- receives grant/research support (all paid to in- stitution, not individual) from Akcea, Amgen, stress testing. Variation may also be at- glomeration of our methodology along Esperion, Novartis, Regeneron, and Sanofi- tributed to misuse or overuse of stress with identification of provider-level Synthelabo and serves as a consultant for Abbott testing due to insufficient knowledge variables, patient outcomes data, and Diagnostics, Akcea, Amarin, Amgen, Arrowhead, e60 Stress Test Variation in Patients With Diabetes Diabetes Care Volume 43, May 2020

AstraZeneca, Corvidia, Denka Seiken, Esperion, manuscript. C.M.B. reviewed and edited the man- 3. Pokharel Y, Gosch K, Nambi V, et al. Practice- Intercept, Matinas BioPharma Inc., Merck, No- uscript. L.A.P. reviewed and edited the manu- level variation in statin use among patients with vartis, Regeneron, and Sanofi-Synthelabo. S.S.V. script. S.S.V. conceptualized the project, researched diabetes: insights from the PINNACLE registry. receives an honorarium from the American data, reviewed and edited manuscript, and revised J Am Coll Cardiol 2016;68:1368–1369 College of Cardiology (Associate Editor for In- the manuscript. S.S.V. is the guarantor of this work 4. Goldstein H. Multilevel Statistical Models. novations, acc.org) and serves on the steering and, as such, had full access to all the data in the John Wiley & Sons, 2011 committee of the Patient and Provider Assess- study and takes responsibility for the integrity 5. WolkMJ,BaileySR,DohertyJU,etal.;American ment of Lipid Management Registry (PALM) at of the data and the accuracy of the data analysis. College of Cardiology Foundation Appropriate Use the Duke Clinical Research Institute (no financial Criteria Task Force. ACCF/AHA/ASE/ASNC/HFSA/ remuneration). No other potential conflicts of HRS/SCAI/SCCT/SCMR/STS 2013 multimodality interest relevant of this article were reported. References appropriate use criteria for the detection and risk Author Contributions. D.M. researched data, 1. Young LH, Wackers FJ, Chyun DA, et al.; DIAD assessment of stable ischemic heart disease: wrote the manuscript, and revised the manu- Investigators. Cardiacoutcomes after screening a report of the American College of Cardiology script. S.T.A. wrote the manuscript. N.R.S. re- for asymptomatic in Foundation Appropriate Use Criteria Task Force, viewed and edited the manuscript. D.J.R. patients with type 2 diabetes: the DIAD study: American Heart Association, American Society of compiled and analyzed the data. J.M.A. concep- a randomized controlled trial. JAMA 2009;301: Echocardiography, American Society of Nuclear tualized the project and reviewed the manu- 1547–1555 Cardiology, Society of America, script. K.N. reviewed and edited the manuscript. 2. Clerc OF, Fuchs TA, Stehli J, et al. Non-invasive Heart Rhythm Society, Society for Cardiovascular I.R.H. reviewed and edited the manuscript. I.Y.E. screening for coronary artery disease in asymp- Angiography and Interventions, Society of Car- reviewed and edited the manuscript. S.W.W. tomatic diabetic patients: a systematic review diovascular Computed Tomography, Society for compiled data and reviewed and edited the and meta-analysis of randomised controlled Cardiovascular Magnetic Resonance, and Society manuscript. M.H.A.-M. reviewed and edited trials. Eur Heart J Cardiovasc Imaging 2018;19: of Thoracic Surgeons. J Am Coll Cardiol 2014;63: the manuscript. H.J. reviewed and edited the 838–846 380–406