Hypothesis / aims of study
Overactive bladder (OAB) remains a common urologic ailment with direct healthcare costs now exceeding 50 billion annually. The American Urology Association (AUA) in conjunction with the Society of Urodynamics, Female Pelvic Medicine, and Urogenital Reconstruction (SUFU) released the clinical guideline on Diagnosis and Treatment of Non-Neurogenic Overactive Bladder (OAB) in Adults in 2012 in order to form a clinical framework for the diagnosis and management of this costly ailment . Per the guidelines, OAB is a clinical diagnosis requiring only a careful history, physical exam, and urinalysis. Further, additional work-up including post-void residual, urodynamics, cytology, and cystoscopy are not necessary in the otherwise uncomplicated patient. The aim of our study is to determine rates of potentially unnecessary diagnostic testing in patients carrying an OAB diagnosis before and after the OAB guidelines publication.
Study design, materials and methods
Using The Atlas Rate Generator exploring a 100% Medicare claims data sample, we identified females with a diagnosis of OAB by ICD-9 codes (596.51 for hypertonicity of bladder, 788.31 for urge incontinence/urinary urgency) within 306 hospital referral regions (HRR). The sample includes patients seen by any provider who makes the diagnosis of OAB, including urologists, urogynecologists, and family practioners. We then identified those beneficiaries with a CPT code for a procedure defined as unnecessary for uncomplicated OAB. Rates of diagnostic tests within HRR were compared to the national average adjusted by age and race, computed as a "observed-to-predicted" ratio.
Figure 1 displays the CPT codes included in the analysis. Rates of diagnostic tests within HRR were compared to the national average adjusted by age and race.
We excluded those beneficiaries who had a CPT code for a third line treatment of OAB (peripheral tibial nerve stimulation, onabotulinum toxin detrusor injection, sacral nerve stimulation).
We collected data from 2011 and 2014, before and after the publication of the AUA/SUFU OAB guidelines.
The national average rate for potentially unnecessary diagnostic procedures performed on patients with OAB was 41% (163,919/399,004) in 2011, and only slightly decreased to 38.2% (169,706/443,512) in 2014. Comparing HRRs to the national rate, use of diagnostic procedures demonstrated 7-fold variation even after controlling for age and race (Figure 1, 2). In 2011 the lowest rate was identified in Minot, ND (0.260) and the highest in Fort Myers, FL (2.036).
By 2014, following the widespread dissemination of the AUA/SUFU guidelines, the lowest rate was identified in Rapid City, SD (0.304) and the highest again in Fort Myers, FL (2.37). Rates of additional procedures were typically highest in the southeast for both years. Figure 2 displays ratio of observed-to-predicted events for diagnostic testing of uncomplicated OAB among female Medicare beneficiaries in 2011 and 2014.
Interpretation of results
There is significant regional variation in utilization of UDS in the diagnosis of OAB at HHR level. The overall rates of unnecessary diagnostic testing did decrease slightly from 2011 to 2014, but not to a significant level. Our results parallel those seen in other specialties where the results of guidelines and publication of randomized control trials do not lead to improvements in clinical practice .
The strengths of our study include the fact that 100% of Medicare female beneficiaries were included. Limitations include our inability to account for coding errors with the claims data. In addition, we were unable to stratify the results according to urologists, urogynecologists, and primary care practitioners. We also did not differentiate between different diagnostic testing, such as post-void residual, which is non-invasive and inexpensive, versus cystoscopy, which is invasive and costly.