Karla Lindquist

Outcomes Insights, Westlake Village, California, United States

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Publications (11)26.7 Total impact

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    ABSTRACT: 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.
    ISRN oncology. 01/2014; 2014:607850.
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    ABSTRACT: 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 ≥66years, 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 1,000 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 12months. 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.
    Gynecologic Oncology 02/2013; · 3.93 Impact Factor
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    ABSTRACT: Background. Trastuzumab improves survival in HER2-positive women with metastatic breast cancer (MBC). The consequences of longer survival include a higher likelihood of additional metastases, including those in the central nervous system (CNS). The effect of CNS metastases on both trastuzumab discontinuation and survival in older patients has not been described. Patients and Methods. We used the Surveillance Epidemiology and End Results (SEER) Medicare data to identify a cohort of 562 women age 66 or older with MBC who were diagnosed between January 1, 2000 and December 31, 2005, free of CNS metastases, and initiated trastuzumab after MBC diagnosis. Time to discontinuation and time to death were analyzed using proportional hazards models. Results. Newly diagnosed CNS metastases were associated with both higher risk of trastuzumab discontinuation (relative hazard [RH] = 1.78, 95% CI 1.11-2.87) and higher risk of death (RH = 2.49, 95% CI 1.84-3.37). The incidence rate of new CNS metastases was comparable among various sites of metastasis (10.7 to 14.7 per 1,000 patient-months), except for bone which was higher (24.1 per 1,000). Conclusion. The diagnosis of CNS metastases was associated with an increase in both the likelihood of discontinuing trastuzumab therapy as well as the risk of death.
    Journal of Cancer Epidemiology 01/2012; 2012:819210.
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    ABSTRACT: Longitudinal analyses of comorbid conditions in women with breast cancer are few. Using Surveillance, Epidemiology, and End Results-Medicare data, we included 51,950 women aged≥66 years with in situ and stage I to IV breast cancer diagnosed in 1998-2002. We identified the prevalence and incidence of 34 comorbid conditions in these women, as well as in a matched cohort without cancer whose rates were standardized to the age and race/ethnicity distribution of the cancer patients. We also estimated rates of office encounters and diagnostic or testing procedures during the 12 months before diagnosis. The prevalence of most conditions at diagnosis was comparable among breast cancer and noncancer patients. New conditions after diagnosis were more common in breast cancer patients, and the incidence rates increased with higher stage at diagnosis. Before diagnosis, women presenting with stage IV disease had 41% [95% confidence interval (CI) 38% to 43%] fewer physician encounters and 34% (95% CI 24% to 31%) fewer unique diagnostic tests than women diagnosed with carcinoma in situ. Many comorbid conditions are identified as a consequence of the breast cancer diagnosis. There appears to be an important contribution from a lack of interaction with the health care system before diagnosis.
    Annals of Oncology 10/2011; 23(7):1756-65. · 7.38 Impact Factor
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    ABSTRACT: Mortality in patients with myelodysplastic syndromes (MDS) is high, and patients are likely to require hospitalizations, emergency department (ED) visits, and transfusions. The relationships between these events and the MDS complications of anemia, neutropenia, and thrombocytopenia are not well understood. A total of 1864 patients registered in the United States' Surveillance Epidemiology and End Results (SEER) program and aged ≥ 66 years old when diagnosed with MDS in 2001 or 2002 were included. Medicare claims were used to identify MDS complications and utilization (hospitalizations, ED visits, and transfusions) until death or the end of 2005. Mortality was based on SEER data. Kaplan-Meier incidence rates were estimated and multivariable Cox models were used to study the association between complications and outcomes. The 3-year incidence of anemia, neutropenia, and thrombocytopenia was 81%, 25%, and 41%, and the incidence of hospitalization, ED visit, and transfusion was 62%, 42%, and 45%, respectively. Median survival time was 22 months. Cytopenia complications were significantly associated with each of these outcomes. All types of cytopenia are common among patients with MDS and are risk factors for high rates of health care utilization and mortality. Management of the complications of MDS may improve patient outcomes.
    Annals of Oncology 11/2010; 22(5):1181-8. · 7.38 Impact Factor
  • Karla Lindquist, Mark D. Danese
    ISCA 19th International Conference on Software Engineeringand Data Engineering (SEDE-2010) June 16-18, 2010, Hilton Fisherman's Wharf, San Francisco, CA, USA; 01/2010
  • Annals of Epidemiology - ANN EPIDEMIOL. 01/2010; 20(9):691-692.
  • Annals of Epidemiology - ANN EPIDEMIOL. 01/2010; 20(9):691-691.
  • Annals of Epidemiology - ANN EPIDEMIOL. 01/2010; 20(9):700-700.
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    ABSTRACT: Immune thrombocytopenic purpura (ITP) is associated with low platelet counts and, consequently, a high risk of adverse events leading to hospitalization. However, there are few data on the clinical and economic burden of hospitalizations for ITP. The Nationwide Inpatient Sample (NIS) database of discharges, a stratified 20% sample of all United States (US) community hospitals across all payers, was used to evaluate discharges in ITP patients. We developed nationally representative numbers of discharges in ITP patients from 2003 to 2006 based on diagnosis codes. Using appropriate weights for each NIS discharge, we created national estimates of average cost, length of stay, and in-hospital mortality for specific groups of ITP-related hospitalizations. Approximately 129,000 discharges occurred between 2003 and 2006 in ITP patients. The average cost associated with all discharges in 2008 dollars was 16,476, with a 6.4-day length of stay and in-hospital mortality of 3.8%. In contrast, the average cost of all hospitalizations in the US population during the same period was 10,039, the average length of stay was 4.8 days, and in-hospital mortality was 2.5%. Mortality risk was higher for ITP patients than for the standard US population adjusted for age and gender, with a relative mortality ratio of 1.5 (95% CI: 1.4-1.6). On the basis of a nationally representative sample of US discharge records from 2003 to 2006, hospitalization with ITP represents an economically and clinically important event. ITP was associated with higher costs, longer stays, and more in-hospital deaths on average than all other hospitalized patients combined.
    American Journal of Hematology 08/2009; 84(10):631-5. · 4.00 Impact Factor
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    ABSTRACT: Splenectomy is a common therapy for adults with chronic idiopathic thrombocytopenic purpura (ITP). Thisstudy was designed to estimate both the short-term surgical non-response rate and the long-term relapse rate after laparoscopic splenectomy. A systematic review was conducted of articles published between January 1, 1991 and January 1, 2008. Selection criteria included: chronic ITP, study enrollment in 1990 or later, > or =12 months of follow-up, > or =15 patients with ITP, > or =75% of patients at least 14 years of age, not HIV positive, not undergoing a second splenectomy, and type of performed splenectomy clearly reported. Data were pooled across studies to estimate rates. We identified 170 articles, of which 23 met our inclusion criteria (all observational studies). These studies represent 1,223 laparoscopic splenectomies (71 or 5.6% were converted to open splenectomy during surgery). The pooled short-term surgical non-response rate among the 18 studies reporting data was 8.2% (95% CI 5.4-11.0). The pooled long-term relapse rate across all 23 studies was 43.6 per 1,000 patient years (95% CI 28.2-67.2). This translates to an approximate failure rate of 28% at 5 years for all patients undergoing splenectomy. Studies with shorter durations of follow-up had significantly higher pooled relapse rates than studies with longer follow-up (P = 0.04). Laparoscopicsplenectomy is effective for most patients. Splenectomy may have higher initial relapse rates, particularly, in the first 2 years after surgery, and the rate may decline over time. Am. J. Hematol. 2009. (c) 2009 Wiley-Liss, Inc.
    American Journal of Hematology 08/2009; 84(11):743-8. · 4.00 Impact Factor