Despite advances in the treatment of aortic stenosis (AS), many patients with AS remain untreated. Barriers to accessing cardiovascular surgical care may play a role in this undertreatment. We sought to examine whether there are geographic variations in the treatment of AS within North Carolina that may reflect differential access to care. Hospital discharge data from North Carolina hospitals during federal fiscal year 2010 were analyzed from the Thomson Reuters database. Patients hospitalized with AS were identified using International Classification of Diseases, ninth revision (ICD-9) diagnosis codes. ICD-9 procedure codes were used to identify patients who had aortic valve replacement and other cardiac procedures. The rates of hospitalizations for AS and aortic valve replacement were calculated per county in North Carolina. In fiscal year 2010, there were 12,111 patients who were discharged from a North Carolina hospital with AS listed as one of the ICD-9 discharge diagnosis codes. The median age for this population was 79 (twenty-fifth to seventy-fifth), with approximately 1/3 patients (28.9%) being at least 85 years of age and >1/2 being female (53.8%). Of them, 1,608 patients underwent valvular surgery with an in-hospital mortality rate of 3.3%. The highest rates, corrected for county population, of hospitalizations where AS was listed as the primary diagnosis were in the most rural segments of North Carolina while those same areas had the lowest rates of valvular surgery. In conclusion, there are significant geographic variations in the rates of hospitalization for AS and for valvular surgery within North Carolina. The most rural segments of the state have the highest rates of hospitalization while also having the lowest rates of surgery. This suggests geographic treatment disparities as a result of access to surgical care that must be considered as new therapies for AS, such as transcatheter aortic valve replacement, are deployed.
The prevalence of aortic stenosis (AS) is growing rapidly, yet it remains significantly undertreated despite recent advances in treatment options. It is estimated that 30–40% of patients with severe symptomatic AS do not receive valve replacement. In 1 multicenter study, only about 1/2 of patients with severe AS were referred for valve replacement therapy, whereas only about 40% of those with severe AS received such therapy. In the Euro Heart Survey, 32% of patients with severe symptomatic valvular disease did not undergo valve surgery, and a meta-analysis and modeling study of AS prevalence in the United States and Europe had similar findings, with 40.5% of patients with severe symptomatic AS not receiving surgical valve replacement. One potential reason for undertreatment may be geographic disparities in access to surgical care, as patients with AS are typically older and less mobile and geographic hurdles to accessing surgical care may play a significant role. Using discharge diagnosis coding data collected from North Carolina hospitals in federal fiscal year 2010, we sought to explore the demographic and geographic distributions of patients hospitalized for aortic valve stenosis and for those who received valvular surgery for AS. In this analysis, we sought to (1) describe the patients hospitalized in North Carolina with aortic valve stenosis, (2) report the number and rate of valvular heart surgeries performed in North Carolina in fiscal year 2010, and (3) to compare the geographic distribution of those hospitalized for aortic valve stenosis versus those who received valvular surgery for AS as a means to explore possible disparities in care based on geographic distribution.
Methods
Hospital discharge data from North Carolina hospitals during federal fiscal year 2010 were analyzed from the Thomson Reuters database. Patients hospitalized with aortic valve stenosis were identified using International Classification of Diseases, ninth revision (ICD-9) diagnosis codes. The following ICD-9 diagnosis codes were used to define aortic valve stenosis: 395.0, 395.2, 396.0, 396.2, 424.1, and 746.3.
Patients with any of the aforementioned ICD-9 diagnosis codes listed as either a primary or nonprimary discharge diagnosis were captured for analysis. All patient information was deidentified and anonymous. The geographic distribution of these patients within North Carolina was determined based on each patient’s home zip code. The total number of patients and the number of patients per 1,000 residents aged ≥65 years were calculated for each county within North Carolina.
To define a subset likely to have been hospitalized more specifically for aortic valve stenosis, we identified patients for whom one of the ICD-9 diagnosis codes for AS was listed as the primary diagnosis on discharge. Furthermore, we excluded any patient who had one of the following ICD-9 diagnosis codes for aortic valve insufficiency in any position: 395.1, 396.1, 396.3, or 746.4. Similarly, we calculated the number of patients meeting this criteria residing within each of the counties of North Carolina and the rate per 1,000 residents aged >65 years in each county.
Co-morbidities for these patients were determined based on the ICD-9 discharge diagnoses. Coronary artery disease, congestive heart failure, stroke, diabetes, and peripheral vascular disease were identified using ICD-9 discharge diagnosis codes. Similarly, in-hospital procedures were determined based on reported ICD-9 procedure codes. The cardiac procedures of cardiac catheterization, percutaneous coronary intervention, right-sided cardiac catheterization, coronary artery bypass grafting, and valvular surgery were identified using ICD-9 procedure codes.
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