Papers by Kristijan Kahler
Irritable bowel syndrome (IBS) has been associat- ed with substantial time lost from work (absent... more Irritable bowel syndrome (IBS) has been associat- ed with substantial time lost from work (absenteeism) and reduced productivity at work (presenteeism), which are the indirect costs of illness. This article presents a productivity model demonstrating the indirect costs associated with IBS and the reduction in those costs for a cohort of female employees hypothetically treated with tegaserod, a new selec-
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The Journal of Rheumatology
In today's cost conscious environment, health services researcher... more In today's cost conscious environment, health services researchers are consistently trying to find ways to predict future health care resource utilization (HCRU) and its associated costs. We evaluated the impact of health related quality of life (HRQL) on future HCRU in patients with arthritis. A total of 642 patients with rheumatoid arthritis (RA) and 395 patients with osteoarthritis (OA) completed at least 2 and as many as 6 consecutive surveys at 6 mo intervals. Information collected included demographics, HRQL questionnaires [Medical Outcome Study Short Form 36 (SF-36), Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), and the Stanford Health Assessment Questionnaire (HAQ)], and HCRU over the previous 6 months. Longitudinal data analysis was perfomed to assess the effect of HRQL on future HCRU. Statistically significant associations between HCRU and HRQL variables were noted. Higher rates of HCRU were found in those in the worst quarter compared with those in the best quarter of HRQL. With the HAQ, OA and RA patients in the worst quarter reported a 199% (p < 0.05) and 48% (p < 0.05) increase in rheumatologist visits, respectively. With the WOMAC Function, increases were as high as 196% (p < 0.05) in rheumatologist visits for patients with OA. Patients with RA with a high level of HRQL as measured by the SF-36 (physical component score) reported a decrease of 31% (p < 0.01) in general practitioner visits and a decrease of 52% (p < 0.01) in hospitalization (mental component score). These findings suggest that HRQL may be used to predict future health care consumption. Such an approach may lead to a more efficient allocation of resources by providing useful information to health care providers and health care decision makers.
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Value in Health, 1999
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The American journal of managed care
This study sought to determine the real-world effectiveness of tegaserod therapy on gastrointesti... more This study sought to determine the real-world effectiveness of tegaserod therapy on gastrointestinal (GI)-related resource utilization in a managed care population with a retrospective, longitudinal pre-/post-parallel cohort study of tegaserod users and a matched reference cohort of tegaserod nonusers through medical and pharmacy claims data from a large, geographically diverse, managed care organization. Continuously enrolled benefit-eligible patients newly initiated on tegaserod therapy (index prescription) were identified between August 1, 2002, and June 30, 2003, and were categorized (using International Statistical Classification of Diseases, 9th Revision, Clinical Modification codes) as having irritable bowel syndrome (IBS) or another GI-related disorder (e.g., gastroesophageal reflux disease). GI-related resource utilization (office visits, hospitalizations, emergency department visits, endoscopic and nonendoscopic procedures, and GI drug prescriptions) was determined for the 6-month period before and after the index prescription date for tegaserod users and nonusers. The study population consisted of 3365 tegaserod users and 3364 matched nonusers. Within-cohort differences before and after therapy were tested using the Wilcoxon signed rank test. The mean age of 3365 tegaserod users and 3364 matched nonusers was 47 years (+/-15 years); 92% were women, 47% had an index diagnosis of IBS, and 53% had an index diagnosis of another GI-related disorder. Within-cohort GI resource utilization comparisons before and after therapy initiation showed significant decreases (P < .01) in all utilization categories, except GI drug prescriptions, for tegaserod users; these decreases were not consistently observed for matched nonusers. Tegaserod use appeared to be associated with consistent decreases in GI-related resource utilization after 6 months of therapy; similarly consistent reductions were not observed in tegaserod nonusers. These early findings suggest that tegaserod may provide important clinical and economic benefits.
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Journal of comparative effectiveness research, Jan 5, 2015
Missing data, particularly missing variables, can create serious analytic challenges in observati... more Missing data, particularly missing variables, can create serious analytic challenges in observational comparative effectiveness research studies. Statistical linkage of datasets is a potential method for incorporating missing variables. Prior studies have focused upon the bias introduced by imperfect linkage. This analysis uses a case study of hepatitis C patients to estimate the net effect of statistical linkage on bias, also accounting for the potential reduction in missing variable bias. The results show that statistical linkage can reduce bias while also enabling parameter estimates to be obtained for the formerly missing variables. The usefulness of statistical linkage will vary depending upon the strength of the correlations of the missing variables with the treatment variable, as well as the outcome variable of interest.
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Value in Health, 2004
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Value in Health, 2015
To compare benefit-risk assessment (BRA) methods for determining whether and when sufficient evid... more To compare benefit-risk assessment (BRA) methods for determining whether and when sufficient evidence exists to indicate that one drug is favorable over another in prospective monitoring. We simulated prospective monitoring of a new drug (A) versus an alternative drug (B) with respect to two beneficial and three harmful outcomes. We generated data for 1000 iterations of six scenarios and applied four BRA metrics: number needed to treat and number needed to harm (NNT|NNH), incremental net benefit (INB) with maximum acceptable risk, INB with relative-value-adjusted life-years, and INB with quality-adjusted life-years. We determined the proportion of iterations in which the 99% confidence interval for each metric included and excluded the null and we calculated mean time to alerting. With no true difference in any outcome between drugs A and B, the proportion of iterations including the null was lowest for INB with relative-value-adjusted life-years (64%) and highest for INB with quality-adjusted life-years (76%). When drug A was more effective and the drugs were equally safe, all metrics indicated net favorability of A in more than 70% of the iterations. When drug A was safer than drug B, NNT|NNH had the highest proportion of iterations indicating net favorability of drug A (65%). Mean time to alerting was similar among methods across the six scenarios. BRA metrics can be useful for identifying net favorability when applied to prospective monitoring of a new drug versus an alternative drug. INB-based approaches similarly outperform unweighted NNT|NNH approaches. Time to alerting was similar across approaches.
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The American journal of managed care, 2005
We sought to develop a budget impact model that assesses the economic effect of adding tegaserod ... more We sought to develop a budget impact model that assesses the economic effect of adding tegaserod for the management of irritable bowel syndrome (IBS) with constipation to the formulary of a managed care organization (MCO). The model estimates the per patient economic impact and the per member, per month (PMPM) economic impact of patients 6 months before and 6 months after the initiation of tegaserod. Resource utilization data, taken from medical and pharmacy administrative claims data, were based on a retrospective, longitudinal study of 3365 patients administered tegaserod through a large, geographically diverse MCO. Costs were estimated for 2 patient subgroups, women with IBS and other gastrointestinal (GI) diagnoses. Sensitivity analyses were performed by varying several model input parameters. The base-case model resulted in an incremental PMPM budget impact associated with the use of tegaserod of 0.01 dollars. Total per patient budget impact (for all resources, including tegase...
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Southern medical journal, 2006
The effectiveness of chronic therapies can be compromised by poor adherence and persistence. Inve... more The effectiveness of chronic therapies can be compromised by poor adherence and persistence. Investigators identified a continuously benefit-eligible cohort of women from a large, geographically diverse, national managed care plan who were newly diagnosed and treated for osteoporosis with alendronate, risedronate, or raloxifene. Drug utilization parameters were evaluated over a 12-month follow-up period for the study population. Adherence was assessed using a medication possession ratio calculated as total days of therapy for medication dispensed/365 days of study follow-up. Persistence was defined as continuous therapy on the same drug for each month over the entire study period. Adherence and persistence were also evaluated for all three study agents in women > or = 65 years of age. In the study cohort (N = 10,566), 12-month adherence/ persistence rates were alendronate 61%/21%, risedronate 58%/19%, and raloxifene 54%/16%. Rates in women > or = 65 years were similar to those...
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The American journal of managed care, 2005
Irritable bowel syndrome (IBS) is a long-term and episodic medical disorder shown to have an impa... more Irritable bowel syndrome (IBS) is a long-term and episodic medical disorder shown to have an impact on work productivity and health-related quality of life (QOL). The objective of this study was to assess the impact of IBS on work productivity and on health-related QOL in an employed population in the United States and to quantify the cost of these factors to the employer. A 2-phase survey was sent to the workforce of a large US bank to assess the presence of IBS among employees and to measure their work productivity (absenteeism [time lost from work] and presenteeism [reduced productivity at work]) and health-related QOL. Forty-one percent of the 1776 employees responding to both phases of the survey met the Rome II criteria for IBS. Employees with IBS reported a 15% greater loss in work productivity because of gastrointestinal symptoms than employees without IBS and had significantly lower Medical Outcomes Study Short Form 36 (SF-36) scores than those without IBS. IBS was associat...
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Value in Health, 2009
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Value in Health, 2015
Patients, physicians, and other decision makers make implicit but inevitable trade-offs among ris... more Patients, physicians, and other decision makers make implicit but inevitable trade-offs among risks and benefits of treatments. Many methods have been proposed to promote transparent and rigorous benefit-risk analysis (BRA). To propose a framework for classifying BRA methods on the basis of key factors that matter most for patients by using a common mathematical notation and compare their results using a hypothetical example. We classified the available BRA methods into three categories: 1) unweighted metrics, which use only probabilities of benefits and risks; 2) metrics that incorporate preference weights and that account for the impact and duration of benefits and risks; and 3) metrics that incorporate weights based on decision makers' opinions. We used two hypothetical antiplatelet drugs (a and b) to compare the BRA methods within our proposed framework. Unweighted metrics include the number needed to treat and the number needed to harm. Metrics that incorporate preference weights include those that use maximum acceptable risk, those that use relative-value-adjusted life-years, and those that use quality-adjusted life-years. Metrics that use decision makers' weights include the multicriteria decision analysis, the benefit-less-risk analysis, Boers' 3 by 3 table, the Gail/NCI method, and the transparent uniform risk benefit overview. Most BRA methods can be derived as a special case of a generalized formula in which some are mathematically identical. Numerical comparison of methods highlights potential differences in BRA results and their interpretation. The proposed framework provides a unified, patient-centered approach to BRA methods classification based on the types of weights that are used across existing methods, a key differentiating feature.
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Value in Health, 2006
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American Journal of Gastroenterology, 2003
Methods: A two-phase, voluntary survey was administered to the workforce of a large US bank with ... more Methods: A two-phase, voluntary survey was administered to the workforce of a large US bank with employees in multiple states. The initial survey collected sociodemographics, gastrointestinal symptom profile and Rome II criteria for IBS, which was used to classify respondents as ...
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American Journal of Gastroenterology, 2003
Purpose: To assess the agreement between 3-vs 12-month Rome II IBS symptom criteria and to assess... more Purpose: To assess the agreement between 3-vs 12-month Rome II IBS symptom criteria and to assess the agreement between the Rome criteria and self-report of a previous medical diagnosis of irritable bowel syndrome (IBS) in an employed US population. ...
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International Journal of Dermatology, 2005
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ClinicoEconomics and Outcomes Research, 2014
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Value in Health, 2009
ABSTRACT
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Value in Health, 2009
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Value in Health, 2008
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Papers by Kristijan Kahler