Treatment patterns, survival, and hospitalization in adult patients with acute lymphoblastic leukemia: an observational cohort study using SEER Medicare data.

There is little evidence about whether additional risk stratification for adult patients with acute lymphoblastic leukemia age 65 and older is warranted. Using the Surveillance, Epidemiology, and End Results data linked to Medicare claims, we examined the effects of age, comorbid conditions, and mobility limitations on treatment and survival in a cohort of 795 patients diagnosed with ALL between 1 January 2000 and 31 December 2009. In the cohort, 54% received chemotherapy within the first 90 days, of whom 74% were hospitalized during the first chemotherapy administration. Unadjusted median survival was 172 days (95% CI = 244-379) for the overall cohort, 325 days (95% CI = 244-379) for those age 65-69, but only 59 days (95% CI = 45-76) for those age ≥80. In multivariate analyses, older age groups (70-74, 75-79, and ≥80) and comorbidity score ≥2 were independently associated with poorer survival. Treatment and outcomes vary considerably among subgroups of older patients suggesting that further risk stratification may be useful.

Second-line therapy in diffuse large B-cell lymphoma (DLBCL): treatment patterns and outcomes in older patients receiving outpatient chemotherapy.

Using SEER-Medicare linked data we identified elderly patients diagnosed with diffuse large B-cell lymphoma (DLBCL) between January 2000 and December 2007 who received second-line outpatient chemotherapy for relapsed or refractory disease. Second-line regimens were classified into three mutually exclusive groups: aggressive, conventional, and palliative. Of the 632 (426 relapsed, 206 refractory) patients in the cohort, 27.8% received aggressive second-line therapy, 39.1% received conventional therapy, and 33.1% received palliative therapy. There were no differences in survival by type of therapy received, either for relapsed or refractory patients, although the patient risk profile differed significantly. However, duration of remission, male gender, and anemia at diagnosis were important predictors in relapsed patients, and male gender, B-symptoms, comorbidity burden, and poverty status were important predictors in refractory patients. Survival in elderly patients receiving second-line therapy remains poor, and the 24-month cost of all care exceeds $97,000. Patients would benefit from improved treatment options.

Racial and Ethnic Variability in the Prevalence and Incidence of Comorbidities Associated with Gastric Cancer in the United States.

PURPOSE: Comorbidities are known to impact quality of life, treatment choices, and survival. Our objectives were to characterize comorbid conditions in a cohort of elderly gastric cancer patients and to determine if there is variability in the prevalence or incidence of the comorbid conditions across racial/ethnic groups. METHODS: A total of 12,612 individuals, ≥66 years of age, diagnosed with gastric cancer between 2000 and 2007, and an equal number of gender- and region-matched cancer-free individuals, were identified using the National Cancer Institute's Surveillance, Epidemiology, and End Results registry linked to Medicare claims in the United States. The prevalence (%) in the year before diagnosis and the 12-month incidence rates after diagnosis were estimated for 32 chronic and ten acute comorbid conditions for the entire cohort and by race/ethnicity (Asian, Black, Hispanic, White, and other) and Asian subgroups (e.g., Chinese, Filipino, Japanese, Pacific Islander). RESULTS: White and Black cases exhibited the highest prevalence of most comorbid conditions. Asian and Pacific Islander cases exhibited the lowest. There was substantial variability in the 12-month incidence of the comorbidities across the racial/ethnic groups. Electrolyte disorder was the most common incident condition among Whites and Blacks. With the exception of Whites, anemia was the most common incident condition in all racial and ethnic groups 180 days following chemotherapy. CONCLUSIONS: There is variability in the prevalence and incidence in comorbidities across racial/ethnic groups.

Estimating the Population Benefits and Costs of Rituximab Therapy in the United States from 1998 to 2013 Using Real-World Data.

BACKGROUND: Rituximab was approved in 1997 and is regularly one of the largest drug expenditures for Medicare; however, its benefits and costs have not been estimated from a population perspective. OBJECTIVES: To estimate both the clinical and the economic outcomes of rituximab for its approved hematological uses at the population level. RESEARCH DESIGN: Analyses using cancer registry incidence data from the Surveillance, Epidemiology, and End Results (SEER) program, and outcomes data from SEER data linked with Medicare administrative claims (SEER-Medicare data). These results were incorporated into an epidemiological simulation model of the population over time. SUBJECTS: We modeled all United States patients from 1998 to 2013 diagnosed with diffuse large B-cell lymphoma, follicular lymphoma, or chronic lymphocytic leukemia. MEASURES: Using this model, we estimated the life-years saved, as well as their economic benefit, in the United States population. We also estimated the incremental cost of adding rituximab to chemotherapy. All economic inputs were based on Medicare reimbursed amounts inflated to 2013 dollars. RESULTS: There were 279,704 cumulative life-years saved which were valued at $25.44 billion. The incremental direct medical cost of rituximab was estimated to be $8.92 billion, resulting in an incremental economic gain of $16.52 billion. CONCLUSIONS: These analyses, based on real-world evidence, show that the introduction of rituximab into clinical practice has produced a substantial number of incremental life-years. Importantly, the economic benefit of the life-years gained greatly exceeds the added costs of treatment.

Impact of undetected comorbidity on treatment and outcomes of breast cancer.

Preexisting comorbidity adversely impacts breast cancer treatment and outcomes. We examined the incremental impact of comorbidity undetected until cancer. We followed breast cancer patients in SEER-Medicare from 12 months before to 84 months after diagnosis. Two comorbidity indices were constructed: the National Cancer Institute index, using 12 months of claims before cancer, and a second index for previously undetected conditions, using three months after cancer. Conditions present in the first were excluded from the second. Overall, 6,184 (10.1%) had ≥1 undetected comorbidity. Chronic obstructive pulmonary disease (38%) was the most common undetected condition. In multivariable analyses that adjusted for comorbidity detected before cancer, older age, later stage, higher grade, and poor performance status all were associated with higher odds of ≥1 undetected comorbidity. In stage I-III cancer, undetected comorbidity was associated with lower adjusted odds of receiving adjuvant chemotherapy (Odds Ratio (OR) = 0.81, 95% Confidence Interval (CI) 0.73-0.90, P < 0.0001; OR = 0.38, 95% CI 0.30-0.49, P < 0.0001; index score 1 or ≥2, respectively), and with increased mortality (Hazard Ratio (HR) = 1.45, 95% CI 1.38-1.53, P < 0.0001; HR = 2.38, 95% CI 2.18-2.60, P < 0.0001; index score 1 or ≥2). Undetected comorbidity is associated with less aggressive treatment and higher mortality in breast cancer.

Undiagnosed diabetes in breast, colorectal, lung, and prostate cancer: incidence and risk factors.

Our study describes the incidence and risk factors for undiagnosed diabetes in elderly cancer patients. Using Surveillance, Epidemiology, and End Results-Medicare data, we followed patients with breast, colorectal, lung, or prostate cancer from 24 months before to 3 months after cancer diagnosis. Medicare claims were used to exclude patients with diabetes 24 to 4 months before cancer (look-back period), identify those with diabetes undiagnosed until cancer, and construct indicators of preventive services, physician contact, and comorbidity during the look-back period. Logistic regression analyses were performed to identify factors associated with undiagnosed diabetes. Overall, 2,678 patients had diabetes undiagnosed until cancer. Rates were the highest in patients with both advanced-stage cancer and low prior primary care/medical specialist contact (breast 8.2%, colorectal 5.9%, lung 4.4%). Nonwhite race/ethnicity, living in a census tract with a higher percent of the population in poverty and a lower percent college educated, lower prior preventive services use, and lack of primary care and/or medical specialist care prior to cancer all were associated with higher (P ≤ 0.05) adjusted odds of undiagnosed diabetes. Undiagnosed diabetes is relatively common in selected subgroups of cancer patients, including those already at high risk of poor outcomes due to advanced cancer stage.

Prevalence and incidence of comorbidities in elderly women with ovarian cancer.

OBJECTIVE: Studies suggest comorbidity plays an important role in ovarian cancer. We characterized the epidemiology of comorbid conditions in elderly U.S. women with ovarian cancer. METHODS: Women with ovarian cancer age ≥66 years, and matched cancer-free women, were identified using the National Cancer Institute's Surveillance, Epidemiology, and End Results registry linked to Medicare claims. Prevalence before diagnosis/index date and 3- and 12-month incidence rates (per 1000 person-years) after diagnosis/index date were estimated for 34 chronic and acute conditions across a broad range of diagnostic categories. RESULTS: There were 5087 each of women with ovarian cancer and cancer-free women. The prevalence of most conditions was similar between cancer and cancer-free patients, but exceptions included hypertension (51.8% and 43.5%, respectively), osteoarthritis (13.4% and 17.3%, respectively), and cerebrovascular disease (8.0% and 9.8%, respectively). In contrast, 3- and 12-month incidence rates (per 1000 person years) of most conditions were significantly higher in cancer than in cancer-free patients: hypertension (177.3 and 47.4, respectively); thromboembolic event (145.3 and 5.5, respectively); congestive heart failure (113.3 and 28.6, respectively); infection (664.4 and 55.2, respectively); and anemia (408.3 and 33.1, respectively) at 12 months. CONCLUSIONS: Comorbidities were common among elderly women. After cancer diagnosis, women with ovarian cancer had a much higher incidence of comorbidities than cancer-free women. The high incidence of some of these comorbidities may be related to the cancer or its treatment, but others may have been prevalent but undiagnosed until the cancer diagnosis. The presence of comorbidities may affect treatment decisions.

Epidemiology and outcomes of previously undiagnosed diabetes in older women with breast cancer: an observational cohort study based on SEER-Medicare.

BACKGROUND: In breast cancer, diabetes diagnosed prior to cancer (previously diagnosed) is associated with advanced cancer stage and increased mortality. However, in the general population, 40% of diabetes is undiagnosed until glucose testing, and evidence suggests one consequence of increased evaluation and management around breast cancer diagnosis is the increased detection of previously undiagnosed diabetes. Biological factors - for instance, higher insulin levels due to untreated disease - and others underlying the association between previously diagnosed diabetes and breast cancer could differ in those whose diabetes remains undiagnosed until cancer. Our objectives were to identify factors associated with previously undiagnosed diabetes in breast cancer, and to examine associations between previously undiagnosed diabetes and cancer stage, treatment patterns, and mortality. METHODS: Using Surveillance, Epidemiology, and End Results-Medicare, we identified women diagnosed with breast cancer and diabetes between 01/2001 and 12/2005. Diabetes was classified as previously diagnosed if it was identified within Medicare claims between 24 and 4 months before cancer diagnosis, and previously undiagnosed if it was identified from 3 months before to ≤ 3 months after cancer. Patients were followed until 12/2007 or death, whichever came first. Multivariate analyses were performed to examine risk factors for previously undiagnosed diabetes and associations between undiagnosed (compared to previously diagnosed) diabetes, cancer stage, treatment, and mortality. RESULTS: Of 2,418 patients, 634 (26%) had previously undiagnosed diabetes; the remainder had previously diagnosed diabetes. The mean age was 77.8 years, and 49.4% were diagnosed with in situ or stage I disease. Age > 80 years (40% of the cohort) and limited health system contact (primary care physician and/or preventive services) prior to cancer were associated with higher adjusted odds of previously undiagnosed diabetes. Previously undiagnosed diabetes was associated with higher adjusted odds of advanced stage (III/IV) cancer (Odds Ratio = 1.37: 95% Confidence Interval (CI) 1.05 - 1.80; P = 0.02), and a higher adjusted mortality rate due to causes other than cancer (Hazard Ratio = 1.29; 95% CI 1.02 - 1.63; P = 0.03). CONCLUSIONS: In breast cancer, previously undiagnosed diabetes is associated with advanced stage cancer and increased mortality. Identifying biological factors would require further investigation.

Impact on Medical Cost, Cumulative Survival, and Cost-Effectiveness of Adding Rituximab to First-Line Chemotherapy for Follicular Lymphoma in Elderly Patients: An Observational Cohort Study Based on SEER-Medicare.

Rituximab improves survival in follicular lymphoma (FL), but is considerably more expensive than conventional chemotherapy. We estimated the total direct medical costs, cumulative survival, and cost-effectiveness of adding rituximab to first-line chemotherapy for FL, based on a single source of data representing routine practice in the elderly. Using surveillance, epidemiology, and end results (SEER) registry data plus Medicare claims, we identified 1,117 FL patients who received first-line CHOP (cyclophosphamide (C), doxorubicin, vincristine (V), and prednisone (P)) or CVP +/- rituximab. Multivariate regression was used to estimate adjusted cumulative cost and survival differences between the two groups over four years after beginning treatment. The median age was 73 years (minimum 66 years), 56% had stage III-IV disease, and 67% received rituximab. Adding rituximab to first-line chemotherapy was associated with higher adjusted incremental total cost ($18,695; 95% Confidence Interval (CI) $9,302-$28,643) and longer adjusted cumulative survival (0.18 years; 95% CI 0.10-0.27) over four years of followup. The expected cost-effectiveness was $102,142 (95% CI $34,531-296,337) per life-year gained. In routine clinical practice, adding rituximab to first-line chemotherapy for elderly patients with FL results in higher direct medical costs to Medicare and longer cumulative survival after four years.

Inverse probability weighted least squares regression in the analysis of time-censored cost data: an evaluation of the approach using SEER-Medicare.

OBJECTIVES: To assess the accuracy and precision of inverse probability weighted (IPW) least squares regression analysis for censored cost data. METHODS: By using Surveillance, Epidemiology, and End Results-Medicare, we identified 1500 breast cancer patients who died and had complete cost information within the database. Patients were followed for up to 48 months (partitions) after diagnosis, and their actual total cost was calculated in each partition. We then simulated patterns of administrative and dropout censoring and also added censoring to patients receiving chemotherapy to simulate comparing a newer to older intervention. For each censoring simulation, we performed 1000 IPW regression analyses (bootstrap, sampling with replacement), calculated the average value of each coefficient in each partition, and summed the coefficients for each regression parameter to obtain the cumulative values from 1 to 48 months. RESULTS: The cumulative, 48-month, average cost was $67,796 (95% confidence interval [CI] $58,454-$78,291) with no censoring, $66,313 (95% CI $54,975-$80,074) with administrative censoring, and $66,765 (95% CI $54,510-$81,843) with administrative plus dropout censoring. In multivariate analysis, chemotherapy was associated with increased cost of $25,325 (95% CI $17,549-$32,827) compared with $28,937 (95% CI $20,510-$37,088) with administrative censoring and $29,593 ($20,564-$39,399) with administrative plus dropout censoring. Adding censoring to the chemotherapy group resulted in less accurate IPW estimates. This was ameliorated, however, by applying IPW within treatment groups. CONCLUSION: IPW is a consistent estimator of population mean costs if the weight is correctly specified. If the censoring distribution depends on some covariates, a model that accommodates this dependency must be correctly specified in IPW to obtain accurate estimates.

Comparative effectiveness and cost of adding rituximab to first-line chemotherapy for elderly patients diagnosed with diffuse large B-cell lymphoma.

BACKGROUND: Clinical trials indicate that rituximab improves the survival of patients with diffuse large B-cell lymphoma (DLBCL). Economic models using multiple data sources, including clinical trials for survival outcomes, have projected cost offsets/savings and favorable cost-effectiveness associated with rituximab. In this study, the authors evaluated survival and cost impacts of adding rituximab to first-line chemotherapy for DLBCL using a single database that reflects routine clinical practice among elderly patients in the United States. METHODS: By using Surveillance, Epidemiology, and End Results (SEER) data linked to Medicare, the authors identified 5484 elderly patients who were diagnosed with DLBCL between January 1999 and December 2005 who had claims through December 2007. Included patients began chemotherapy with or without rituximab within 180 days of diagnosis. Multivariate analyses were conducted to estimate the impact of rituximab on mortality and costs to Medicare. The cost per life-year gained of rituximab was calculated using cost and survival estimates from the multivariate analyses. RESULTS: The mean patient age was 76 years, 43% of patients had stage III or IV disease, and 64% received rituximab. In a Cox regression model, rituximab resulted in lower 4-year all-cause mortality (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.61-0.74) and cancer mortality, and the incremental cumulative survival was 0.37 years. In least-squares regression, rituximab resulted in higher 4-year total costs ($23,097; 95% CI, $19,129-$27,298), immunochemotherapy costs ($12,069; 95% CI, $10,687-$13,634), other cancer costs ($7655; 95% CI, $5067-$10,489), and noncancer costs ($3461; 95% CI, $1319-$5650). The cost per life-year gained was $62,424. CONCLUSIONS: In routine clinical practice, rituximab was associated with survival benefits comparable to those observed in clinical trials. However, these benefits did not translate into the previously reported cost savings.

Granulocyte-colony stimulating factor use and medical costs after initial adjuvant chemotherapy in older patients with early-stage breast cancer.

BACKGROUND: Granulocyte-colony stimulating factor (G-CSF) reduces the risk of severe neutropenia associated with chemotherapy, but its cost implications following chemotherapy are unknown. OBJECTIVE: Our objective was to examine associations between G-CSF use and medical costs after initial adjuvant chemotherapy in early-stage (stage I-III) breast cancer (ESBC). METHODS: Women diagnosed with ESBC from 1999 to 2005, who had an initial course of chemotherapy beginning within 180 days of diagnosis and including ≥1 highly myelosuppressive agent, were identified from the Surveillance, Epidemiology, and End Results (SEER)-Medicare database. Medicare claims were used to describe the initial chemotherapy regimen according to the classes of agents used: anthracycline ([A]: doxorubicin or epirubicin); cyclophosphamide (C); taxane ([T]: paclitaxel or docetaxel); and fluorouracil (F). Patients were classified into four study groups according to their G-CSF use: (i) primary prophylaxis, if the first G-CSF claim was within 5 days of the start of the first chemotherapy cycle; (ii) secondary prophylaxis, if the first claim was within 5 days of the start of the second or subsequent cycles; (iii) G-CSF treatment, if the first claim occurred outside of prophylactic use; and (iv) no G-CSF. Patients were described by age, race, year of diagnosis, stage, grade, estrogen (ER) and progesterone (PR) receptor status, National Cancer Institute (NCI) Co-morbidity Index, chemotherapy regimen and G-CSF use. Total direct medical costs ($US, year 2009 values) to Medicare were estimated from 4 weeks after the last chemotherapy administration up to 48 months. Medical costs included those for ESBC treatment and all other medical services received after chemotherapy. Least squares regression, using inverse probability weighting (IPW) to account for censoring within the cohort, was used to evaluate adjusted associations between G-CSF use and costs. RESULTS: A total of 7026 patients were identified, with an average age of 72 years, of which 63% had stage II disease, and 59% were ER and/or PR positive. Compared with no G-CSF, those receiving G-CSF primary prophylaxis were more likely to have stage III disease (30% vs. 16%; p < 0.0001), to be diagnosed in 2003-5 (87% vs. 26%; p < 0.0001), and to receive dose-dense AC-T (26% vs. 1%; p < 0.0001), while they were less likely to receive an F-based regimen (12% vs. 42%; p < 0.0001). Overall, the estimated average direct medical cost over 48 months after initial chemotherapy was $US 42,628. In multivariate analysis, stage II or III diagnosis (compared with stage I), NCI Co-morbidity Index score 1 or ≥2 (compared with 0), or FAC or standard AC-T (each compared with AC) were associated with significantly higher IPW 48-month costs. Adjusting for patient demographic and clinical factors, costs in the G-CSF primary prophylaxis group were not significantly different from those not receiving primary prophylaxis (the other three study groups combined). In an analysis that included four separate study groups, G-CSF treatment was associated with significantly greater costs (incremental cost = $US 2938; 95% CI 285, 5590) than no G-CSF. CONCLUSIONS: Direct medical costs after initial chemotherapy were not statistically different between those receiving G-CSF primary prophylaxis and those receiving no G-CSF, after adjusting for potential confounders.