| Summary: | 碩士 === 高雄醫學大學 === 臨床藥學研究所 === 99 === BACKGROUND: Irritable bowel syndrome (IBS) is a chronic, relapsing, functional gastrointestinal disorder and causing long-term disturbances to patients. However, the impacts of IBS on patients'' quality of life (QoL) and social and economic costs are generally nelegected in health care systm. This study aimed to assess the current best evidence on the efficacy of drug treatments for IBS, evaluate medical utilization of Taiwanese irritable bowel syndrome patients, and to explore the impacts of IBS on patients and underlying attributes to QoL.
METHODS: This study can be divided into three parts. The first part is a systematic review on clincail efficacy and economic evaluations. An electronic database search on PubMed, EMBASE and the Cochrane Controlled Trials Register (up to Jan 2010) were conducted to include double blind, randomized clinical trials (RCT) and economic evaluation studies of drug treatment on IBS. Quality of included studies were evaluations and data were extracted for futher meta-anlaysis. The second part is a cross-sectional study conducted from 2004 to 2008 using a nationwide sampled, longitudinal claim-based database (LHID2005) constituting of a million beneficiaries randomly sampled in 2005. Adult IBS outpatients who have recived drug treatments were identified by diagnosis codes and ATC codes. The medical and drug utilization were analyzed by descriptive statistic, and monthly trends were analyzed by simple linear regression. The third part is a qualitative study; semi-structure interviews were conducted at a reginal hospital in southern Taiwan from July 2010 to December 2010. A topic guide was used to ensure a systematic coverage of attributes related to QoL during the interview. Meanwhile, health-related quality of life was measured by standard gamble (SG), EuroQol (EQ-5D) questionnaire and visual analogue scale (EQ-5D VAS) during the interview.
RESULTS: There are 11 included placebo-control RCTs (8,512 patients). Overall, a significantly higher proportion of patients with drugs treatment achieved relief in disease-related symptoms (RR: 1.45; 95%CI: 1.28, 1.69; p<0.0001) and abdominal pain or discomfort (RR: 1.35; 95%CI: 1.35, 1.51; p<0.0001) comparing against placebo.
There are 5 economic evaluation studies identified, including cost-effectiveness analysis (n=1) , budget impact analysis (n=1) and cost-consequences analysis (n=1) and cost-utility analysis (n=2). Data source for economic evlautions mainly came from randomized, controlled clinical trials (n=3), and most research subjects were female (80% to 100%). Only one study has included a detail cost category other than direct medical costs, i.e. direct medical costs, direct non-medical costs and indirect costs. All of the five studies have conducted and reported sensitivity analysis and incremental analysis.
Of all, 40,890 IBS outpatients (mean age 49.8±17.6 years; 55.0% female) and 1,451 IBS outpatients receiving long-term drug treatment were identified from LHID2005. The overall number of visits and total outpatient medical expenditure significantly increased (p<0.05) during study period. Antispasmodics and propulsive agents were the most frequently prescribed. Defined daily doses of all classes of drugs for IBS symptom control also significantly increased (p<0.05).
Twenty-nine adult IBS outpatients (mean age 45.8±16.5 years; 62.1% female) were successfully interviewed during study period. The utility measured in standard gamble (0.85±0.16) was higher than EQ-5D index (0.79±0.15). The long-term and recurrent abdominal pain or discomfort affected participants’ efficiency of work or study and reduced their willingness to participate in social activities. In addition, these symptoms also raised their further worries and stress. However, due to the worries about the adverse drug reactions, the participants only took medicine when their symptoms were not controled.
CONCLUSIONS: Currently clinical studies for IBS treatments mainly focus on newly developed agents (5-HT3 antagonists and 5-HT4 agonists). However, head-to-head studies and the evidence of treatment effects on long-term functions or quality of life are still lacking and subject to further research. Only a few well-defined and good quality economic evaluations were found associated with IBS drug treatment. However, there was still no consistence on the study designs and definitions. In Taiwan, only a few of patients with IBS receiving long-term drug treatment, but medical and drug utilization of IBS patients have been increasing. The IBS epidemiological characteristics in Taiwan are different from European countries and United States. For patients with potentially moderate to severe IBS and consistent medical treatments, the functional impairment was still tolerable yet intangible (anxiety, worries) and social stress may had greater impacts on QoL. To conduct economic evaluation studies on Taiwanese IBS patients in the future, appropriate and feasible measures to assess the effective and QoL, is and using real life individual patient data are necessary.
|
|---|
