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The American Journal of Managed Care August 2013
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Cost of Care for Malignant and Benign Renal Masses
Aviva G. Asnis-Alibozek, PA-C; Michael J. Fine, MD; Paul Russo, MD; Trent McLaughlin, BSc(Pharm), PhD; Eileen M. Farrelly, MPH; Norman LaFrance, MD; and William Lowrance, MD, MPH
Potential Misuse and Inappropriate Prescription Practices Involving Opioid Analgesics
Ying Liu, PhD; Joseph E. Logan, PhD; Leonard J. Paulozzi, MD, MPH; Kun Zhang, MS; and Christopher M. Jones, PharmD
Does Medication Adherence Lead to Lower Healthcare Expenses for Patients With Diabetes?
Shou-Hsia Cheng, PhD; Chi-Chen Chen, PhD; and Chin-Hsiao Tseng, MD, PhD
False Activation of the Cardiac Catheterization Laboratory for Primary PCI
Geoffrey D. Barnes, MD; Alexander Katz, MD; Jeffrey S. Desmond, MD; Steven L. Kronick, MD, MS; Jamie Beach, RN; Stanley J. Chetcuti, MD; Eric R. Bates, MD; and Hitinder S. Gurm, MD
Option Pricing: A Flexible Tool to Disseminate Shared Savings Contracts
Mark W. Friedberg, MD, MPP; Anthony M. Buendia, BA; Katharine E. Lauderdale, BA; and Peter S. Hussey, PhD
Sources of Information Used in Selection of Surgeons
Caroline S. Carlin, PhD; John Kralewski, PhD; and Megan Savage, BS
A Natural Experiment in Mass Media Modulated Pharmacokinetics After a Change in Tablet Formulation
Natan R. Kahan, PhD, RPh, MHA; Daniel A. Vardy, MD, MSc; Dan-Andrei Waitman, MD, MPH; and Gherta Brill, MD

Cost of Care for Malignant and Benign Renal Masses

Aviva G. Asnis-Alibozek, PA-C; Michael J. Fine, MD; Paul Russo, MD; Trent McLaughlin, BSc(Pharm), PhD; Eileen M. Farrelly, MPH; Norman LaFrance, MD; and William Lowrance, MD, MPH
Methods for better identifying malignant versus benign disease before nephrectomy could provide significant benefits to patients and payers.
Background: Limitations of current diagnotic techniques may allow some patients with presumed renal cell carcinoma (RCC) to undergo nephrectomy without definitive confirmation of malignancy.

Objectives: To confirm previous estimates of postnephrectomy renal mass diagnosis and to assess the economic impact of nephrectomy.

Methods: This retrospective cohort analysis identified commercial enrollees who underwent nephrectomy with a diagnosis of RCC between July 1, 2000, and March 30, 2008. Study subjects were stratified based on medical claims for benign or malignant disease after the nephrectomy date. Cohorts were compared on resource utilization before and after nephrectomy, occurrence of postsurgical complications, and associated 1-year costs of care.

Results: Of 10,404 patients undergoing nephrectomy for presumed RCC, 1613 (15.5%) were subsequently identified as having benign disease, despite median presurgical diagnostic expenditures of $1311 per patient (interquartile range [IQR], $467-$2606). Median expenditures for the 12 months postnephrectomy were $26,920 per patient (IQR, $16,851-$46,982) for those with malignant disease  and $23,951 per patient (IQR, $14,873-$38,190) for those with benign disease (P <.0001). For patients with benign disease, 17.5% experienced a postsurgical adverse event, resulting in a 1.5-fold increase in expenditures (median $31,838 per patient for those with event vs $22,770 per patient for those without event; P <.0001).

Conclusions: In this study, approximately 1 in 6 patients were found to have a benign renal mass  postnephrectomy. Given the risk of surgical complications and related economic consequences, methods for better identifying malignant versus benign disease prior to surgery could provide significant benefits to patients and payers.

Am J Manag Care. 2013;19(8):617-624
This analysis of insured Americans suggests that 1 in 6 patients who undergo nephrectomy for suspected renal cell carcinoma are subsequently found to have benign disease.
  • The median cost of this care, inclusive of and within 12 months of surgery, was $26,405 per patient.

  • Among those with complications after nephrectomy, expenditures may exceed $40,000 per patient in the year following surgery.

  • Assuming 58,000 new renal tumors will be detected annually using currently available diagnostic techniques in the United States and treated surgically without tissue confirmation of cancer, the American healthcare system might be resourcing upward of 10,000 potentially avoidable nephrectomies each year.
Renal cell carcinoma (RCC) accounts for approximately 3% of adult malignancies and more than 80% of kidney cancers, causing approximately 13,000 deaths in the United States each year.1-3 It is typically characterized by a lack of early warning signs, diverse clinical manifestations, and tumor resistance to radiation and traditional chemotherapy.

The increasingly prevalent use of cross-sectional imaging for nonspecific abdominal complaints has resulted in the earlier diagnosis of RCC and a preponderance of small asymptomatic lesions. Thus, the continual rise in RCC incidence is attributed largely to enhanced detection, with more than 70% of kidney cancers now being discovered incidentally and at a size less than 7 cm.4-8 Nephron-sparing surgery is gaining acceptance as the treatment of choice for these smaller tumors, while radical nephrectomy remains the standard for larger tumors not amenable to partial nephrectomy.

Differentiating between benign and malignant renal tumors through current radiographic or clinical methods remains a challenge. While renal biopsy for molecular analysis of tissues might provide additional information in this setting, it yields nondiagnostic information in up to 20% of cases and is often available only at academic centers.9

Importantly, previous research suggests that approximately 20% of patients who undergo nephrectomy are found to have benign postoperative tumor histology, implying the possibility of surgical overtreatment.10-15 Based on current estimates of 58,000 patients with new RCC diagnoses in the United States each year, the vast majority of whom will undergo nephrectomy prior to a definitive tissue confirmation of cancer, it is conceivable that the American healthcare system is resourcing upward of 10,000 potentially avoidable nephrectomies each year.16

The objectives of this analysis were to confirm previous estimates of postnephrectomy renal mass diagnosis and to assess the economic impact of nephrectomy, both in terms of surgical costs and resource utilization related to postoperative complications, in a large population of commercially insured Americans.

MATERIALS AND METHODS

Database

Data were obtained from the IMS LifeLink Database, which at the time of the study was composed of medical and pharmaceutical claims for approximately 60 million unique patients from 100 health plans, including health maintenance organizations (HMOs), preferred provider organizations (PPOs), point-of-service (POS) plans, indemnity plans, and other types, located throughout the United States. The database includes both inpatient and outpatient diagnoses (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] codes) and procedures (Current Procedural Terminology, Version 4 [CPT-4] and Healthcare Common Procedure Coding System codes), as well as both standard and mail order pharmacy records. Data elements include demographic variables (age, sex, geographic region), health plan type (eg, HMO, PPO, POS), payer type (eg, commercial, self-pay), provider specialty, reimbursed amount for service, date of service, and start and stop dates for plan enrollment.

Because all pertinent patient information in the database is encrypted and de-identified, and no patient contact was involved, no informed consent or approval by an institutional review board was required or sought. The data source was fully Health Insurance Portability and Accountability compliant.

Sample Selection

Patients were eligible for analysis if they had at least 2 medical claims for RCC (defined as ICD-9-CM codes 189.0, 189.1, 198.0, 236.91) during the July 1, 2000, through March 30, 2008, database extraction period. Patients were further required to have a claim for nephrectomy (CPT-4 codes 50220, 50225, 50230, 50234, 50236, 50240, 50543, 50545, 50546, 50547, 50548) during the study period to be included in the analysis (note that the nephrectomy claim could coincide with 1 of the 2 required RCC diagnoses). A minimum of 2 ICD-9-CM RCC diagnoses were required to ensure all patients included in the study presented with a high preoperative clinical suspicion of presumed renal malignancy.

The date of the nephrectomy claim during that period was assigned as the index date. From that date, 6 months of preindex and up to 12 months of postindex data were collected for all health plan–eligible patients. Patients had to have continuous health plan enrollment for 6 months before and at least 6 months after the index date to ensure complete baseline and follow-up information on all patients in the study.

Study Groups

Two mutually exclusive study groups were identified based on medical claims. Patients were categorized as ultimately having either benign disease or malignant disease following the nephrectomy. Benign disease was defined as any patient having a medical claim with a benign diagnosis (ICD-9-CM codes benign neoplasm, kidney, except pelvis [223.0], renal pelvis [223.1]) subsequent to the index date (nephrectomy).To be conservative regarding the prevalence of benign disease postnephrectomy, all other patients (ie, those with a minimum of 2 medical claims for a diagnosis of RCC, but with no benign diagnosis subsequent to the nephrectomy) were considered to have malignant disease.

Measures

The postnephrectomy benign and malignant cohorts were compared with respect to patient demographics (age, sex, region of the United States where surgery was performed), surgery type (nephron sparing vs radical nephrectomy), and comorbid conditions (using Charlson Comorbidity Index score, individual comorbidities contributing to the score).17,18 In addition, rates of nephrectomy-related adverse events were calculated for each cohort: hemorrhage (ICD-9-CM 998.1x), deep vein thrombosis (ICD-9-CM 453.40, 453.41, 453.42), pulmonary embolism (ICD-9-CM 415.11, 415.12, 415.19), myocardial infarction (ICD-9-CM 410.x), surgical woundinfection or disruption (ICD-9-CM 686.9, 998.31, 998.32), renal or perinephric abscess (ICD-9-CM 590.2), sepsis (ICD-9-CM 038.0, 038.1, 038.2, 038.3, 038.4, 038.8), acute renal failure (ICD-9-CM 584.xx, 586.xx), and pneumothorax (ICD-9-CM 512.0, 512.1, 512.8) were all considered to be acute adverse events and were measured during the first 30 days after surgery.

Chronic kidney disease (ICD-9-CM 584.xx, 585.xx, 586. xx), dialysis (CPT-4 90935, 90937, 90945, 90947, 90968, 90969, 90970), and renal transplantation (CPT-4 50300, 50320, 50323, 50325, 50327, 50328, 50329, 50340, 50360, 50365, 50370, 50380) were considered to be long-term adverse events and were measured from 30 days after surgery up to 12 months following the date of the nephrectomy.

Finally, resource utilization prior to and following the nephrectomy was assessed and summarized for the 2 cohorts. In the period prior to nephrectomy, cost estimates were specific for the use of diagnostic procedures, including angiography (CPT-4 72191, 72198, 74175, 74185), renal biopsy (CPT-4 50200, 50205, 50555, 52354), computed tomography (CT) scan (CPT-4 72192, 72193, 72194, 74150, 74160, 74170), magnetic resonance imaging scan (CPT-4 72195, 72196, 72197, 74181, 74182, 74183), positron-emission tomography scan (CPT-4 78814, 78815, 78816), or ultrasound (CPT-4 76700, 76705, 76770, 76775, 93975). Following the nephrectomy, total medical expenditures were calculated and stratified based on the presence or absence of the adverse events listed above. Cost estimates during the postnephrectomy study period were represented as the total amount of payments made by third-party payers for inpatient, outpatient, pharmacy, and other medical claims.

Statistical Analysis

Comparisons of categorical variables were conducted using the x2 test, while continuous variables were assessed using univariate analysis of variance, with an a priori level of significance of P = .05. To account for the comparisons across multiple cohorts, a Bonferroni’s adjustment (0.05 per 6 contracts = 0.008) was performed. All analyses were performed using SAS version 9.2 (SAS Institute Inc, Cary, North Carolina).

RESULTS

As shown in Figure 1, a total of 10,404 eligible patients were identified during the study period with at least 2 medical claims consistent with an RCC diagnosis and a medical claim for a nephrectomy. All patients were tracked for 6 months prenephrectomy and followed a minimum of 6 months postnephrectomy, with a median follow-up of 12 months (interquartile range [IQR], 12-12 months).

Demographic information for the included patients is presented in Figure 2 and Figure 3. A total of 1613 patients, or 15.5% of the sample, had medical claims indicative of benign disease subsequent to their nephrectomy date. These patients were more often female (48.4% vs 37.4%; P <.01), were less likely to undergo radical nephrectomy (63.3% vs 78.5%; P <.01), and had fewer comorbid conditions as evidenced by the mean Charlson Comorbidity Index scores (2.4 [standard deviation 2.5]) vs 3.0 [standard deviation 2.8]; P <.01), than patients with a retained malignant diagnosis. Duration of postnephrectomy follow-up was identical between the benign and malignant cohorts.

During the study period, median medical expenditures for diagnostic procedures performed prior to the nephrectomy (preindex date) were $1311 (IQR, $467-$2606) per patient. This cost was driven primarily by use of preoperative imaging procedures such as CT scans, with more than 90% of study patients having at least 1 CT scan, and 3689 (35.5% overall, 36.9% in benign cohort, 35.2% in malignant cohort) having 2 or more CT procedures during the preindex study period. Use of diagnostic tests (Table 1) and associated expenditures (Figure 4) were similar across the benign and malignant cohorts. Biopsy was performed in fewer than 10% of all patients (4% in benign cohort, 10% in malignant). In contrast to preindex resource utilization, median expenditures incurred from date of admission to discharge and deemed related directly to the nephrectomy procedure were $17,793 (IQR, $10,068-$24,718) per patient, with the median length of inpatient hospital stay being 5 days (IQR, 4-7 days).

Approximately 17% of patients experienced at least 1 surgical complication within 30 days of the nephrectomy (Table 2). The most common acute events were acute renal failure (6.5% and 7.9% of patients with benign and malignant disease, respectively; P = .05), pneumothorax (3.8% and 3.4% of patients with benign and malignant disease, respectively; P = .43), and hemorrhage (2.6% and 2.9% of patients with benign and malignant disease, respectively; P = .48). Longterm effects (those documented between 30 days and up to 12 months postnephrectomy) were less common, occurring in approximately 4% of patients overall. New diagnosis of chronic kidney disease accounted for the majority of cases (2.4% and 3.3% of patients with benign and malignant disease,respectively; P = .06), followed by dialysis (1.4% and 2.7% of patients with benign and malignant disease, respectively;P <.01).

 
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