Irritable Bowel Syndrome Is Associated Not Only With Organic but Also Psychogenic Erectile Dysfunction

C-Y Hsu; C-L Lin; C-H Kao


Int J Impot Res. 2015;27(6):233-238. 

In This Article

Materials and Methods

Data Source

Data used in this study were obtained from reimbursement claims of the National Health Insurance (NHI) Program in Taiwan, which was implemented in 1995 and covers >99% of 23.74 million Taiwan residents. The National Health Research Institutes (NHRI) established a National Health Insurance Research Database (NHIRD). All the identifiers of individual patients are deleted by the NHIR before data are transferred to the NHIRD. The NHRI has released a cohort data set comprised of one million randomly selected cases from the registry of NHI beneficiaries during 2000 (Longitudinal Health Insurance Database 2000; LHID2000). The NHRI followed all of the aforementioned randomly sampled patients to Year 2011. This study was approved by the Institutional Review Board (CMU-REC-101-012). The International Classification of Disease, 9th Revision, Clinical Modification (ICD-9-CM) was used to identify health status.

Sampled Participants

We selected male patients aged >20 years, who were diagnosed with IBS (ICD-9-CM codes 564.1) during the 2000–2011 period as the IBS cohort. The index date for patients with IBS was the date of their first medical visit. We excluded patients with a diagnosis of OED and PED (ICD-9-CM codes 607.84 and 302.72) at baseline and those without information on age and sex. For the non-IBS cohort, we used a simple random sampling method and selected four control patients without a history of IBS, who were excluded according to the same criteria as those of the IBS cohort. The IBS patients and non-IBS controls were frequency matched for age (every 5-year span), sex, monthly income, urbanization level and index year.


We identified the first diagnosis of OED and PED as the study end point. Person-years of follow-up were calculated for each patient until OED and PED was diagnosed, death occurred, the patients withdrew from the insurance system or until the end of 2011.

Variables of Interest

The sociodemographic variables used in this study comprised age (20–34 years, 35–49 years, 50–64 years and ≥65 years), monthly income and urbanization level. The subjects' monthly costs for insurance premiums were classified into 3 groups of <15 000; 15 000–19 999; and ≥20 000 New Taiwan Dollars (1.0 USD is ~30 NTD). The urbanization level was categorized by the population density of the residential area, population ratio of the elderly, agriculture workers, different educational levels and the number of physicians per 100 000 people into 4 levels, with level 1 as the most urbanized and level 4 as the least urbanized. We considered several well-known risk factors of OED and PED including coronary artery disease (CAD; ICD-9 code 410–414), chronic obstructive pulmonary disease (COPD; ICD-9 codes 490–496), chronic kidney disease (CKD; ICD-9 codes 580–589), hypertension (ICD-9 codes 401–405), diabetes (ICD-9 code 250), hyperlipidemia (ICD-9 code 272), depression (ICD-9 code 296.2, 296.3, 300.4, 311) and anxiety (ICD-9 code 300.00), to be the comorbidities. A medical history of antihypertensive drug, antidepressants drug and benzodiazepines use was included in the analysis.

Statistical Analysis

We used the χ 2-test to determine the differences in categorical sociodemographic variables, comorbidities and medications between the IBS cohort and the non-IBS cohort, and used the Student's t-test to examine the mean ages and follow-up time (years) between both cohorts. The overall, age- and comorbidity-specific incidence rates (per 10 000 person-year) were calculated for each cohort. The IBS to non-IBS cohort hazard ratio (HR) and 95% confidence interval (CI) were estimated using the univariable and multivariable Cox proportional hazards regression model. The multivariable-adjusted models included all statistically significant covariates in the univariable Cox model. The Kaplan–Meier method was used to plot the cumulative incidence of OED and PED, and a log-rank test was used to compare the cohorts. All analyses were performed using the statistical package SAS for Windows (Version 9.3, SAS Institute Inc., Carey, NC, USA). A two-tailed P<0.05 was considered statistically significant.