Assessing the Saskatchewan database for outcomes research studies of depression and its treatment

Incidence of Poststroke Depression in Patients With Poststroke Dysphagia

PURPOSE

Poststroke dysphagia and poststroke depression (PSD) can have devastating effects on stroke survivors, including increased burden of care, higher health care costs, poor quality of life, and greater mortality; however, there is a dearth of research examining depression in patients diagnosed with dysphagia after stroke. Thus, we aimed to study the incidence of PSD in patients with poststroke dysphagia to provide foundational knowledge about this patient population.

METHOD

We conducted a retrospective, cross-sectional study of individuals with a primary diagnosis of acute ischemic stroke (AIS) and secondary diagnoses of dysphagia and/or depression using administrative claims data from the 2017 Medicare 5% Limited Data Set.

RESULTS

The proportion of depression diagnosis in patients with poststroke dysphagia was significantly higher than the proportion of depression diagnosis in those without poststroke dysphagia during acute hospitalization: 12.01% versus 9.52%, respectively (p = .003).

CONCLUSIONS

Our results demonstrated that persons with poststroke dysphagia were as, or slightly more, likely to have PSD compared to the general stroke population, and to our knowledge, they establish the first reported incidence of PSD in Medicare patients with dysphagia after AIS. Future research is warranted to further explore the effects of PSD on poststroke dysphagia.

Diagnoses of Depression and Anxiety Versus Current Symptoms and Quality of Life in Multiple Sclerosis

BACKGROUND

Studies assessing the prevalence of depression and anxiety in multiple sclerosis (MS) have used various ascertainment methods that capture different constructs. The relationships between these methods are incompletely understood. Psychiatric comorbidity is associated with lower health-related quality of life (HRQOL) in MS, but the effects of past diagnoses of depression and anxiety on HRQOL are largely unknown. We compared the prevalence of depression and anxiety in persons with MS using administrative data, self-reported physician diagnoses, and symptom-based measures and compared characteristics of persons classified as depressed or anxious by each method. We evaluated whether HRQOL was most affected by previous diagnoses of depression or anxiety or by current symptoms.

METHODS

We linked clinical and administrative data for 859 participants with MS. HRQOL was measured by the Health Utilities Index Mark 3. We classified participants as depressed or anxious using administrative data, self-reported physician diagnoses, and the Hospital Anxiety and Depression Scale. Multivariable linear regression examined whether diagnosed depression or anxiety affected HRQOL after accounting for current symptoms.

RESULTS

Lifetime prevalence estimates for depression were approximately 30% regardless of methods used, but 35.8% with current depressive symptoms were not captured by either administrative data or self-reported diagnoses. Prevalence estimates of anxiety ranged from 11% to 19%, but 65.6% with current anxiety were not captured by either administrative data or self-reported diagnoses. Previous diagnoses did not decrease HRQOL after accounting for current symptoms.

CONCLUSIONS

Depression and, to a greater extent, anxiety remain underdiagnosed and undertreated in MS; both substantially contribute to reduced HRQOL in MS.

Risk of Miscarriage in Women Receiving Antidepressants in Early Pregnancy, Correcting for Induced Abortions

BACKGROUND

Earlier studies on the association between antidepressant use and miscarriage have obtained conflicting results after accounting for the role of depression, and none have taken into account the high risk of induced abortions in women using antidepressants.

METHODS

We identified 41,964 pregnant women delivering between 1998 and 2002 using Quebec's health administration databases. We compared women prescribed antidepressants in the first trimester and with a recorded diagnosis of depression before pregnancy to (1) women with neither antidepressant use nor a depression diagnosis before or during pregnancy; (2) women with a depression diagnosis before pregnancy, but no antidepressants prescribed in the first trimester; and (3) women prescribed hypothyroid medication in the first trimester, but not antidepressants. We used log binomial regression to assess the adjusted relative risk of miscarriage, corrected for induced abortion risk.

RESULTS

The miscarriage risk uncorrected for induced abortions was 16%, 10%, and 9% for depressed women exposed to antidepressants; unexposed depressed women; and unexposed, nondepressed women, respectively. These decreased to 11%, 8%, and 7% after correction for induced abortions. In multivariable analysis, the corrected risk of miscarriage relative to unexposed, nondepressed women was 1.3 (1.1-1.5) for antidepressant-exposed women and 1.1 (1.0-1.2) for unexposed depressed women. The miscarriage relative risk for antidepressant users compared with unexposed depressed women was thus 1.2 (1.0-1.4).

CONCLUSIONS

Antidepressant use in the first trimester is associated with an increased risk of miscarriage when compared with either nondepressed or depressed unexposed women, even after accounting for induced abortions.

Performance of administrative case definitions for depression and anxiety in inflammatory bowel disease

OBJECTIVES

Comorbid depression and anxiety are common in inflammatory bowel disease (IBD), but few population-based estimates of the burden of depression and anxiety exist. Methods to support population-based studies are needed. We aimed to test the performance of administrative case definitions for depression and anxiety in IBD and to understand what the prevalence estimated using such definitions reflects.

METHODS

We linked administrative (health claims) data from the province of Manitoba, Canada with clinical data for 266 persons in the Manitoba IBD Cohort Study. We compared the performance of administrative case definitions for depression and anxiety with (a) diagnoses of depression and anxiety as identified based on the Composite International Diagnostic Interview (CIDI), which identifies disorders meeting formal diagnostic criteria, and (b) participant report of physician-diagnosed depression or anxiety.

RESULTS

Administrative definitions for depression showed moderate agreement with the CIDI (κ=0.39-0.42). Agreement was higher with participant report of physician-diagnosed depression (κ=0.54). The lifetime prevalence of depression was 29.3% based on the CIDI, 17.7% based on participant report of physician-diagnosed depression, and 21.8-22.5% based on administrative data. Compared to the CIDI, administrative definitions for anxiety showed fair agreement (κ=0.21-0.25). The lifetime prevalence of anxiety was 31.2% based on the CIDI, 9.7% based on participant report of physician-diagnosed anxiety, and 24.4-31.9% based on administrative data.

CONCLUSIONS

Administrative data may be used for population-level surveillance of depression and anxiety in IBD, although they will not capture undiagnosed or untreated cases.

A Surveillance System to Monitor Excess Mortality of People With Mental Illness in Canada

OBJECTIVE

Outcome measures are rarely available for surveillance and system performance monitoring for mental disorders and addictions. Our study aims to demonstrate the feasibility and face validity of routinely measuring the mortality gap in the Canadian context at the provincial and regional levels using the methods and data available to the Canadian Chronic Disease Surveillance System (CCDSS) of the Public Health Agency of Canada.

METHODS

We used longitudinal data from the Quebec Integrated Chronic Disease Surveillance System, which also provides aggregated data to the CCDSS. This includes data from the health insurance registry physician claims and the hospital discharge abstract for all mental disorder diagnoses (International Classification of Diseases [ICD]-9 290-319 or ICD-10 F00-F99). Patients were defined as having had received a mental disorder diagnosis at least once during the year. Life expectancy was measured using Chiang's method for abridged life tables, complemented by the Hsieh method for adjustment of the last age interval.

RESULTS

We found a lower life expectancy among psychiatric patients of 8 years for men and 5 years for women. For patients with schizophrenia, life expectancy was lowered by 12 years for men and 8 years for women. Cardiovascular disease and cancer were the most common causes of premature death. Findings were consistent across time and regions of the province. Lower estimates of the mortality gap, compared with literature, could be explained by the inclusion of primary care patients and methods.

CONCLUSIONS

Our study demonstrates the feasibility of using administrative data to measure the impact of current and future mental health plans in Canada provided the techniques can be replicated in other Canadian provinces.

Relationship Between Depressive State and Treatment Characteristics of Acute Cervical Spinal Cord Injury in Japan

Background

Few studies have assessed whether treatment of acute cervical spinal cord injury (SCI) patients contributes to depression.

Methods

Using an administrative database, we assessed patients for whom the diagnosis was unspecified injuries of cervical spinal cord (International Classification of Diseases and Injuries-10th (ICD-10) code; S14.1). We categorized patients with codes for depressive episode (ICD-10 code; F32) or recurrent depressive disorder (F33), or those prescribed antidepressants (tricyclic, tetracyclic, Selective Serotonin Reuptake Inhibitors, Serotonin Noradrenaline Reuptake Inhibitors, Trazodone, Sulpiride, or Mirtazapine) as having a depressive state. We compared the rate of each acute treatment between the depressive state group and the non-depressive state group using chi-square tests, and a multiple logistic regression model was used to identify the association between the acute treatment and depressive state.

Results

There were 151 patients who were judged to be in a depressive state, and the other 2115 patients were categorized into the non-depressive state group. Intervention of intravenous anesthesia, tracheostomy, artificial respiration, and gastrostomy had a significant positive correlation with depressive state. Multiple logistic regression analysis showed that tracheostomy (odds ratio [OR] 2.18; 95% confidence interval [CI], 1.09–4.38) and artificial respiration (OR 2.28; 95% CI, 1.32–3.93) were significantly associated with depressive state, and men had a 36% reduction in the risk of depressive state compared with women (OR 0.64; 95% CI, 0.44–0.94), whereas age, wound-treatment, all of the orthopedic procedures, intravenous anesthesia, and gastrostomy were not associated with depressive state.

Conclusions

These findings suggest that tracheostomy, artificial respiration and female gender in the acute phase after cervical SCI might be associated with the development of depression.

Comparing algorithms for deriving psychosis diagnoses from longitudinal administrative clinical records

PURPOSE

Registers derived from administrative datasets are valuable tools in psychosis research, but diagnostic accuracy can be problematic. We sought to compare the relative performance of four methods for assigning a single diagnosis from longitudinal administrative clinical records when compared with reference diagnoses.

METHODS

Diagnoses recorded in inpatient and community mental health records were compared to research diagnoses of psychotic disorders obtained from semi-structured clinical interviews for 289 persons. Diagnoses were derived from administrative datasets using four algorithms; 'At least one' diagnosis, 'Last' or most recent diagnosis, 'Modal' or most frequently occurring diagnosis, and 'Hierarchy' in which a diagnostic hierarchy was applied. Agreements between algorithm-based and reference diagnoses for overall presence/absence of psychosis and for specific diagnoses of schizophrenia, schizoaffective disorder, and affective psychosis were examined using estimated prevalence rates, overall agreement, ROC analysis, and kappa statistics.

RESULTS

For the presence/absence of psychosis, the most sensitive and least specific algorithm ('At least one' diagnosis) performed best. For schizophrenia, 'Modal' and 'Last' diagnoses had greatest agreement with reference diagnosis. For affective psychosis, 'Hierarchy' diagnosis performed best. Agreement between clinical and reference diagnoses was no better than chance for diagnoses of schizoaffective disorder. Overall agreement between administrative and reference diagnoses was modest, but may have been limited by the use of participants who had been screened for likely psychosis prior to assessment.

CONCLUSION

The choice of algorithm for extracting a psychosis diagnosis from administrative datasets may have a substantial impact on the accuracy of the diagnoses derived. An 'Any diagnosis' algorithm provides a sensitive measure for the presence of any psychosis, while 'Last diagnosis' is more accurate for specific diagnosis of schizophrenia and a hierarchical diagnosis is more accurate for affective psychosis.

Antidepressant use and risk for preeclampsia

BACKGROUND

Prior studies suggest that women who use antidepressants during pregnancy have an increased risk for preeclampsia, yet the comparative safety of specific antidepressants remains unclear. US nationwide Medicaid Analytic eXtract (MAX) data have not been used to study medication safety during pregnancy.

METHODS

We identified 100,942 pregnant women with depression from 2000 to 2007 MAX data. We used pharmacy dispensing records to ascertain exposure to selective serotonin reuptake inhibitor (SSRI), serotonin-norepenephrine reuptake inhibitor (SNRI), tricyclic, bupropion, other antidepressant monotherapy or polytherapy, and specific antidepressants, during the second trimester and first half of the third trimester. Relative risks (RRs) and 95% confidence intervals (CIs) were adjusted for delivery year, preeclampsia risk factors, depression severity proxies, other antidepressant indications, other medications, and healthcare utilization.

RESULTS

The risk of preeclampsia was 5.4% among women with depression and no antidepressant exposure. Compared with these women, the risk for preeclampsia was higher among those receiving SNRI (RR: 1.52, 95% CI = 1.26-1.83) and tricyclic monotherapy (RR: 1.62, 95% CI = 1.23-2.12), but not SSRI monotherapy (RR: 1.00, 95% CI = 0.93-1.07) or other antidepressants. Compared with women receiving SSRI monotherapy, preeclampsia risk was higher among women with SNRI (RR: 1.54, 95% CI = 1.28-1.86) and tricyclic (RR: 1.64, 95% CI = 1.25-2.16) monotherapy. None of the specific SSRIs was associated with preeclampsia. The RR with venlafaxine was 1.57 (95% CI = 1.29-1.91) and with amitriptyline 1.72 (95% CI = 1.24-2.40).

CONCLUSIONS

In this population, SNRIs and tricyclics were associated with a higher risk of preeclampsia than SSRIs.

Use of antidepressants near delivery and risk of postpartum hemorrhage: cohort study of low income women in the United States

OBJECTIVE

To determine whether use of serotonin or non-serotonin reuptake inhibitors near to delivery is associated with postpartum hemorrhage.

DESIGN

Cohort study.

SETTING

2000-07 nationwide Medicaid data (Medicaid Analytic eXtract).

POPULATION

106,000 pregnant women aged 12-55 with a diagnosis of mood or anxiety disorder. Women were categorized into four mutually exclusive exposure groups according to pharmacy dispensing data: current (delivery date), recent (1-30 days before delivery date), past (1-5 months before delivery date), and no exposure (reference group).

MAIN OUTCOME MEASURES

Risk of postpartum hemorrhage by timing of exposure and by serotonin or non-serotonin reuptake inhibitors, classes of antidepressant, and antidepressant types. Relative risks and 95% confidence intervals adjusted for delivery year, risk factors for postpartum hemorrhage, indicators of severity of mood/anxiety disorder, other indications for antidepressants, and other drugs. High dimensional propensity score (hdPS) methods were used to empirically identify and adjust for additional factors.

RESULTS

12,710 (12%) women had current exposure to serotonin reuptake inhibitor monotherapy, and 1495 (1.4%) women had current exposure to non-serotonin reuptake inhibitor monotherapy. The risk of postpartum hemorrhage was 2.8% among women with mood/anxiety disorders but no exposure to antidepressants, 4.0% in the current users of serotonin reuptake inhibitors, 3.8% in the current users of non-serotonin reuptake inhibitors, 3.2% in the recent users of serotonin reuptake inhibitors, 3.1% in the recent users of non-serotonin reuptake inhibitors, 2.5% in the past users of serotonin reuptake inhibitors, and 3.4% in the past users of non-serotonin reuptake inhibitors. Compared with no exposure, women with current exposure to serotonin reuptake inhibitors had a 1.47-fold increased risk of postpartum hemorrhage (95% confidence interval 1.33 to 1.62) and women with current non-serotonin reuptake inhibitor exposure had a 1.39-fold increased risk (1.07 to 1.81). Results were similar with hdPS adjustment. Women with current exposure to serotonin reuptake inhibitors had an adjusted excess risk of 1.26% (0.90% to 1.62%), with a number needed to harm of 80, and for women with current exposure to non-serotonin reuptake inhibitors the excess risk was 1.03% (0.07% to 1.99%), with a number needed to harm of 97. For exposure to serotonin reuptake inhibitors the relative risk was 1.19 (1.03 to 1.38) for recent exposure and 0.93 (0.82 to 1.06) for past exposure; for non-serotonin reuptake inhibitors the figures were 1.17 (0.80 to 1.70) and 1.26 (1.00 to 1.59), respectively. Current exposure to selective serotonin reuptake inhibitor monotherapy was also associated with postpartum hemorrhage (1.42, 1.27 to 1.57), as was current serotonin norepinephrine (noradrenaline) reuptake inhibitor (1.90, 1.37 to 2.63) and tricyclic monotherapy (1.77, 0.90 to 3.47). All types of selective serotonin reuptake inhibitors available for analysis and venlafaxine, a serotonin norepinephrine reuptake inhibitor, were significantly associated with postpartum hemorrhage.

CONCLUSIONS

Exposure to serotonin and non-serotonin reuptake inhibitors, including selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and tricyclics, close to the time of delivery was associated with a 1.4 to 1.9-fold increased risk for postpartum hemorrhage. While potential confounding by unmeasured factors cannot be ruled out, these findings suggest that patients treated with antidepressants during late pregnancy are more likely to experience postpartum hemorrhage.

Mental comorbidity and multiple sclerosis: validating administrative data to support population-based surveillance

Background

While mental comorbidity is considered common in multiple sclerosis (MS), its impact is poorly defined; methods are needed to support studies of mental comorbidity. We validated and applied administrative case definitions for any mental comorbidities in MS.

Methods

Using administrative health data we identified persons with MS and a matched general population cohort. Administrative case definitions for any mental comorbidity, any mood disorder, depression, anxiety, bipolar disorder and schizophrenia were developed and validated against medical records using a a kappa statistic (k). Using these definitions we estimated the prevalence of these comorbidities in the study populations.

Results

Compared to medical records, administrative definitions showed moderate agreement for any mental comorbidity, mood disorders and depression (all k ≥ 0.49), fair agreement for anxiety (k = 0.23) and bipolar disorder (k = 0.30), and near perfect agreement for schizophrenia (k = 1.0). The age-standardized prevalence of all mental comorbidities was higher in the MS than in the general populations: depression (31.7% vs. 20.5%), anxiety (35.6% vs. 29.6%), and bipolar disorder (5.83% vs. 3.45%), except for schizophrenia (0.93% vs. 0.93%).

Conclusions

Administrative data are a valid means of surveillance of mental comorbidity in MS. The prevalence of mental comorbidities, except schizophrenia, is increased in MS compared to the general population.

Elevated risk of preeclampsia in pregnant women with depression: depression or antidepressants?

A previous study suggested an increased risk of preeclampsia among women treated with selective serotonin reuptake inhibitors (SSRIs). Using population-based health-care utilization databases from British Columbia (1997-2006), the authors conducted a study of 69,448 pregnancies in women with depression. They compared risk of preeclampsia in women using SSRIs, serotonin-norepinephrine reuptake inhibitors (SNRIs), or tricyclic antidepressants (TCAs) between gestational weeks 10 and 20 with risk in depressed women not using antidepressants. Among prepregnancy antidepressant users, the authors compared the risk in women who continued antidepressants between gestational weeks 10 and 24 with the risk in those who discontinued. Relative risks and 95% confidence intervals were estimated. The risk of preeclampsia in depressed women not treated with antidepressants (2.4%) was similar to that in women without depression (2.3%). Compared with women with untreated depression, women treated with SSRI, SNRI, and TCA monotherapy had adjusted relative risks of 1.22 (95% confidence interval (CI): 0.97, 1.54), 1.95 (95% CI: 1.25, 3.03), and 3.23 (95% CI: 1.87, 5.59), respectively. Within prepregnancy antidepressant users, the relative risk for preeclampsia among continuers compared with discontinuers was 1.32 (95% CI: 0.95, 1.84) for SSRI, 3.43 (95% CI: 1.77, 6.65) for SNRI, and 3.26 (95% CI: 1.04, 10.24) for TCA monotherapy. Study results suggest that women who use antidepressants during pregnancy, especially SNRIs and TCAs, have an elevated risk of preeclampsia. These associations may reflect drug effects or more severe depression.

Do contact precautions cause depression? A two-year study at a tertiary care medical centre

Contact precautions, used to reduce the transmission of infectious diseases, include the wearing of gowns and gloves for room entry. Previous small studies have shown an association between contact precautions and increased symptoms of depression and anxiety. A retrospective cohort of all patients admitted to a tertiary care centre over two years was studied to assess the relationship between contact precautions and depression or anxiety. During the two-year period, there were 70,275 admissions including 28,564 unique non-intensive-care-unit (ICU), non-psychiatric admissions. After adjusting for potential confounders, contact precautions were associated with depression [odds ratio (OR) 1.4, 95% confidence interval (CI) 1.2-1.5] but not with anxiety (OR 0.8, 95% CI 0.7-1.1) in the non-ICU population. Depression was 40% more prevalent among general inpatients on contact precautions.

Antidepressants and fracture risk in older adults: a comparative safety analysis

We examined variations in fracture rates among patients initiated on antidepressant drug treatment as identified from Medicare data in two US states and assessed whether the observed variation could be explained by affinity for serotonin transport receptors. We used Cox proportional hazards models to compare fracture rates of the hip, humerus, pelvis, wrist, and a composite of these, among propensity score-matched cohorts of users of secondary amine tricyclics, tertiary amine tricyclics, selective serotonin reuptake inhibitors (SSRIs), and atypical antidepressants. As compared with secondary amine tricyclics, SSRIs showed the highest association with composite fracture rate (hazard ratio 1.30; 95% confidence interval (CI) 1.12-1.52), followed by atypical antidepressants (hazard ratio 1.12; 95% CI 0.96-1.31) and tertiary amine tricyclics (hazard ratio 1.01; 95% CI 0.87-1.18). The results were robust to sensitivity analyses. Although SSRI use was associated with the highest rate of fractures, variation in fracture risk across specific antidepressant medications did not depend on affinity for serotonin transport receptors.

Patterns of antidepressant use in Quebec children and adolescents: trends and predictors

Antidepressants are highly prescribed in youth although most products have not been approved for use in this population. Furthermore, regulatory warnings have led to changes in antidepressant use that might have differed across various countries. Our study aimed at determining factors associated with antidepressant prescribing practices and at assessing trends in use from 1997 to 2005 in Quebec youth.A retrospective cohort study was conducted through claims databases of the Quebec public health care program (RAMQ). The study included 5094 children (age 2-14) and 11,121 adolescents (age 15-19) who were incident users of antidepressant between 1997 and 2005. The characteristics of users and prescribers were the main independent variables.Tricyclics were the most frequently dispensed products among children (50.9%) and selective serotonin reuptake inhibitors among adolescents (58.8%). Selection of an antidepressant class was associated with patient characteristics and with prescriber specialty. The number of antidepressant users increased from 1997 until 2001 then decreased thereafter.The selection of an antidepressant class was associated with clinical and non-clinical characteristics. Although antidepressant use decreased after regulatory warnings, there appears to be a care gap between the evidence generated by efficacy studies and the products prescribed in a real-life setting.

Health advisories and patterns of patient monitoring among new users of antidepressant medications

INTRODUCTION

In 2003, more intense monitoring of patients initiating antidepressants was advised because of emerging concerns of suicidality. We sought to identify patterns of patient monitoring after antidepressant initiation in British Columbia before and after issuance of health advisories.

MATERIALS AND METHODS

We conducted a cohort study of antidepressant initiators between 1999 and 2005 using healthcare utilization data of all British Columbia residents. For the periods before (1999-2001) and after (2004-2005), health advisories concerning suicidality associated with antidepressants, we assessed monitoring intensity by calculating weekly physician and psychotherapy visit rates since antidepressant initiation. We also estimated monitoring patterns as the proportion of individuals who received weekly in-person contact during the first 4 weeks of treatment, then biweekly visits for 4 weeks, and then a visit at 12 weeks, as a proxy for intensive monitoring.

RESULTS

Patterns of monitoring intensity were similar before and after the health advisories, but the level of intensity was lower after the advisory period. Overall, monitoring intensity peaked in the 4 weeks after antidepressant initiation. Weekly numbers of visits per subject during these 4 weeks were between 0.44 and 0.49 before the advisory and from 0.39 to 0.44 after the advisory. Among all initiators stratified by year of initiation, between 21% and 25% received intensive monitoring, and this proportion generally decreased on a yearly basis.

DISCUSSION

Monitoring intensity for patients with depression initiating antidepressants decreased after the period of emergence and greater awareness of the association between antidepressants and suicidality.

Data enhancement for co-morbidity measurement among patients referred for sleep diagnostic testing: an observational study

Background

Observational outcome studies of patients with obstructive sleep apnea (OSA) require adjustment for co-morbidity to produce valid results. The aim of this study was to evaluate whether the combination of administrative data and self-reported data provided a more complete estimate of co-morbidity among patients referred for sleep diagnostic testing.

Methods

A retrospective observational study of 2149 patients referred for sleep diagnostic testing in Calgary, Canada. Self-reported co-morbidity was obtained with a questionnaire; administrative data and validated algorithms (when available) were also used to define the presence of these co-morbid conditions within a two-year period prior to sleep testing.

Results

Patient self-report of co-morbid conditions had varying levels of agreement with those derived from administrative data, ranging from substantial agreement for diabetes (κ = 0.79) to poor agreement for cardiac arrhythmia (κ = 0.14). The enhanced measure of co-morbidity using either self-report or administrative data had face validity, and provided clinically meaningful trends in the prevalence of co-morbidity among this population.

Conclusion

An enhanced measure of co-morbidity using self-report and administrative data can provide a more complete measure of the co-morbidity among patients with OSA when agreement between the two sources is poor. This methodology will aid in the adjustment of these coexisting conditions in observational studies in this area.

Validity of the diagnosis of a single depressive episode in a case register

Objective

To validate the ICD-10 diagnosis of a single depressive episode as used in daily clinical psychiatric practice and as recorded in the Danish Psychiatric Central Research Register.

Methods

Patients discharged with a diagnosis of a single depressive episode were consecutively sampled from the register and diagnosed according to an interview using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN).

Results

A total of 75.4% of 399 patients with a register diagnosis of a single depressive episode also got this diagnosis according to the SCAN interview (82.8% for severe type of a single depression, 76.0% for moderate type of a single depression and 65.2% for mild type of a single depression).

Conclusion

The ICD-10 diagnosis of a single depressive episode can be used in daily clinical practice with sufficient precision. The validity of the diagnosis is highest for severe and moderate type of depression and decreases for mild depression.

Agreement between administrative databases and medical charts for pregnancy-related variables among asthmatic women

PURPOSE

To determine the validity of pregnancy variables recorded in administrative databases of Quebec using patient medical charts as the gold standard among asthmatic pregnant women.

METHODS

Three administrative databases were linked and provided information on maternal, pregnancy and infant characteristics for 726 pregnant asthmatic women who delivered in 1990-2000. Algorithms were developed to measure variables that were not recorded directly in the databases or to minimize the number of missing values for variables recorded in two or more databases. Medical file data were collected by two trained research nurses in 43 hospitals. The validity of categorical variables was assessed with sensitivity, specificity, predictive positive values (PPVs) and predictive negative values (PNVs), whereas the validity of continuous variables was assessed with Pearson correlation using the medical chart as the gold standard.

RESULTS

The sensitivity of the sex of the baby, previous live birth and previous pregnancy ranged from 0.97 to 0.99. Corresponding figures were 0.92-0.98 for specificity. We also found high correlation coefficients, ranging from 0.875 to 0.999 for the length of gestation, dates of last menstruation and delivery, maternal age and birth weight.

CONCLUSION

Pregnancy-related variables recorded in administrative databases or derived from algorithms based on two or more databases were found to be highly valid as compared to the medical chart among asthmatic women.

Type of antidepressant therapy and risk of type 2 diabetes in people with depression

OBJECTIVE

The objective of this study was to evaluate the differential risk of diabetes among people with depression taking antidepressant therapy.

METHODS

A nested case control design was used to investigate the study objective. Data from the Canadian province of Saskatchewan was available from January 1, 1991 to December 31, 2001; the average length of follow-up was 4.07 years. Type 2 diabetes was identified based on ICD-9 diagnostic codes and antidiabetic medication prescriptions; prior depression was ascertained based on ICD-9 diagnostic codes and antidepressant prescriptions.

RESULTS

Multivariate logistic regression analysis was used to estimate the odds ratio (OR) and 95% confidence intervals (CI). We identified 2391 individuals with incident depression treated with antidepressant therapy. The mean age was 53.6 (S.D.: 16.4) and 68% were female. After multivariate adjustment, the concurrent use of selective serotonin reuptake inhibitors (SSRI) and tricyclic antidepressants (TCA) was associated with a significantly increased risk of type 2 diabetes (adjusted OR: 1.89; 95% CI: 1.35-2.65).

CONCLUSIONS

Concurrent use of TCA and SSRI was associated with an increased risk of developing type 2 diabetes compared to using TCA alone. Individuals taking combination TCA and SSRI therapy should be closely monitored for development of type 2 diabetes.

Recognition of depression in older medical inpatients

BACKGROUND

Studies of recognition of depression in older (aged 65 or more) medical inpatients show low rates of recognition of depression by attending physicians. However, few studies have compared different measures of recognition of depression.

OBJECTIVES

(1) To compare the validity of four indicators of recognition of depression and a global measure of recognition against a diagnosis of depression and (2) to explore the effect of patient characteristics on recognition of depression.

METHODS

In a cohort of 264 medical inpatients 65 years and older (115 with major or minor depression, 78 with no depression), sensitivities, specificities, and diagnostic odds ratios (DOR) of 4 indicators of recognition (symptoms, diagnosis, treatment, and referral) and a global measure of recognition (any of the 4 indicators) were calculated. The associations between patient characteristics (age, sex, history of depression, antidepressant use before admission, severity of depression, comorbidity, duration of hospitalization, disability, and hospital of admission) and recognition were explored using multiple logistic regression.

RESULTS

Less than half of the depressed patients were recognized. The indicator with the highest sensitivity was treatment (27.8%, 95% confidence interval [CI] 20.0-37.0), whereas the indicator with the best specificity was diagnosis (96.6%, 95% CI 91.9-98.7). The unadjusted DOR of global recognition was 2.6 (95% CI 1.5, 4.4). Less comorbidity, more severe depression symptoms, a history of depression, longer hospital stay, and antidepressant use before admission were significantly associated with better global recognition.

CONCLUSION

Recognition of depression in elderly medical inpatients depends upon the indicator of recognition used.

Accuracy of medicare claims data in identifying Parkinsonism cases: Comparison with the medicare current beneficiary survey

STUDY PURPOSE

Administrative databases are commonly used to examine use of healthcare service, with researchers relying on diagnostic codes to identify medical conditions. This study evaluates the accuracy of administrative claims in identifying Parkinsonism cases compared to the self-reported Parkinson's disease (PD).

METHODS

The reference cases were identified based on the self-reported PD status and the use of PD drugs collected by the 1992-2000 Medicare Current Beneficiary Survey that contained 72,922 observations from 30,469 individuals. Using ICD-9 CM, cases with PD were extracted from the corresponding Medicare claims. We compared prevalence of PD obtained using different types of claims.

RESULTS

The sensitivities were the highest when all claims were used (66%). All the specificities were greater than 99%. When drug use information was included in the gold standard, the sensitivities became lower, while the specificities and positive predictive values (PPVs) increased. Using more diagnostic codes improved the sensitivity of the identification process but reduced PPVs.

CONCLUSIONS

Administrative claims can provide fairly accurate and practical approach to "rule in" patients with PD. Depending on the purpose of evaluation, researchers may consider using more categories of claims to improve the sensitivity of the identification algorithm or use fewer diagnoses to minimize number of false positive cases.

Diagnostic variability for schizophrenia and major depression in a large public mental health care system dataset

Administrative datasets can provide information about mental health treatment in real world settings; however, an important limitation in using these datasets is the uncertainty regarding psychiatric diagnosis. To better understand the psychiatric diagnoses, we investigated the diagnostic variability of schizophrenia and major depression in a large public mental health system. Using schizophrenia and major depression as the two comparison diagnoses, we compared the variability of diagnoses assigned to patients with one recorded diagnosis of schizophrenia or major depression. In addition, for both of these diagnoses, the diagnostic variability was compared across seven types of treatment settings. Statistical analyses were conducted using t tests for continuous data and chi-square tests for categorical data. We found that schizophrenia had greater diagnostic variability than major depression (31% vs. 43%). For both schizophrenia and major depression, variability was significantly higher in jail and the emergency psychiatric unit than in inpatient or outpatient settings. These findings demonstrate that the variability of psychiatric diagnoses recorded in the administrative dataset of a large public mental health system varies by diagnosis and by treatment setting. Further research is needed to clarify the relationship between psychiatric diagnosis, diagnostic variability and treatment setting.

Data quality in an information-rich environment: Canada as an example

This review evaluates the quality of available administrative data in the Canadian provinces, emphasizing the information needed to create integrated systems. We explicitly compare approaches to quality measurement, indicating where record linkage can and cannot substitute for more expensive record re-abstraction. Forty-nine original studies evaluating Canadian administrative data (registries, hospital abstracts, physician claims, and prescription drugs) are summarized in a structured manner. Registries, hospital abstracts, and physician files appear to be generally of satisfactory quality, though much work remains to be done. Data quality did not vary systematically among provinces. Primary data collection to check place of residence and longitudinal follow-up in provincial registries is needed. Promising initial checks of pharmaceutical data should be expanded. Because record linkage studies were ''conservative'' in reporting reliability, the reduction of time-consuming record re-abstraction appears feasible in many cases. Finally, expanding the scope of administrative data to study health, as well as health care, seems possible for some chronic conditions. The research potential of the information-rich environments being created highlights the importance of data quality.

Validity of asthma diagnoses recorded in the Medical Services database of Quebec

The goal of this study was to evaluate the validity of asthma diagnoses recorded in the Medical Services (physician billing) database of the Canadian province of Quebec. The predictive positive value (PPV) and predictive negative value (PNV) of two operational definitions of asthma based on diagnoses recorded in the database were evaluated. Patients 16-80 years old treated by a respiratory or a family physician in 2002 were selected from the database. The diagnosis derived from the Medical Services database was compared to the diagnosis written in the patient's medical chart. The PPV and PNV of the first operational definition based on one asthma diagnosis or more recorded in the database over a 1-year period were found to be 0.75 and 0.96 for respiratory physicians and 0.67 and 0.99 for family physicians, for patients 16-44 years old. The PPV increased to 0.78 for family physicians and to 0.77 for respiratory physicians when the second operational definition based on two diagnoses of asthma or more was used. Results tended to be lower for 45-80 years old patients. We conclude that diagnoses recorded in the Medical Services database of Quebec are valid to identify patients with asthma.

Type 2 diabetes does not increase risk of depression

BACKGROUND

Although diabetes mellitus has a strong association with the presence of depression, it is unclear whether diabetes itself increases the risk of developing depression. The objective of our study was to evaluate whether people with diabetes have a greater incidence of depression than those without diabetes.

METHODS

We conducted a population-based retrospective cohort study using the administrative databases of Saskatchewan Health from 1989 to 2001. People older than 20 years with newly identified type 2 diabetes were identified by means of diagnostic codes and prescription records and compared with a nondiabetic cohort. Depression was ascertained via diagnostic codes and prescriptions for antidepressants. Cox regression analysis was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) after adjusting for age, sex, frequency of visits to physicians and presence of comorbidities.

RESULTS

We identified 31 635 people with diabetes and 57 141 without. Those with diabetes were older (61.4 v. 46.8 yr; p < 0.001), were more likely to be male (55.4% v. 49.8%; p < 0.001) and had more physician visits during the year after their index date (mean 14.5 v. 5.9; p < 0.001). The incidence of new-onset depression was similar in both groups (6.5 v. 6.6 per 1000 person-years among people with and without diabetes, respectively). Similarity of risk persisted after controlling for age, sex, number of physician visits and presence of prespecified comorbidities (adjusted HR 1.04, 95% CI 0.94- 1.15). Other chronic conditions such as arthritis (HR 1.18) and stroke (HR 1.73) were associated with the onset of depression.

INTERPRETATION

Using a large, population-based administrative cohort, we found little evidence that type 2 diabetes increases the risk of depression once comorbid diseases and the burden of diabetes complications were accounted for.

Selective serotonin reuptake inhibitors and adverse pregnancy outcomes

OBJECTIVE

The purpose of this study was to assess the safety of the use of selective serotonin reuptake inhibitors in pregnancy.

STUDY DESIGN

We carried out a retrospective cohort study of 972 pregnant women who had been given at least 1 selective serotonin reuptake inhibitor prescription in the year before delivery and 3878 pregnant women who did not receive selective serotonin reuptake inhibitors and who were matched by the year of the infant's birth, the type of institute at birth, and the mother's postal code from 1990 to 2000 in the Canadian province of Saskatchewan.

RESULTS

The risks of low birth weight (adjusted odds ratio, 1.58; 95% CI, 1.19, 2.11), preterm birth (adjusted odds ratio, 1.57; 95% CI, 1.28, 1.92), fetal death (adjusted odds ratio, 2.23; 95% CI, 1.01, 4.93), and seizures (adjusted odds ratio, 3.87; 95% CI, 1.00, 14.99) were increased in infants who were born to mothers who had received selective serotonin reuptake inhibitor therapy.

CONCLUSION

The use of selective serotonin reuptake inhibitors in pregnancy may increase the risks of low birth weight, preterm birth, fetal death, and seizures.

Administrative registers in psychiatric research: a systematic review of validity studies

OBJECTIVE

To conduct a systematic review of studies investigating the validity of administrative registers for use in psychiatric research.

METHOD

Studies were identified using MEDLINE (1966-2004) and EMBASE (1980-2004) databases using keywords 'validity' or 'reliability' combined with 'register' or 'database$'. Studies reviewed by two raters blind to each other and quality assessed using a data extraction form devised by the authors. A narrative description of the findings is presented.

RESULTS

Fourteen studies were identified, seven of which concerned Scandinavian registers. Ten studies were solely concerned with diagnostic validity and the most common single diagnosis studied was schizophrenia (five studies). Methods used and study quality varied widely.

CONCLUSION

Given the importance of the area, relatively little high-quality work exists into systematically measuring the diagnostic data validity of registers for research purposes.

Accuracy of coding for possible warfarin complications in hospital discharge abstracts

BACKGROUND

Hospital discharge abstracts could be used to identify complications of warfarin if coding for bleeding and thromboembolic events are accurate.

OBJECTIVES

To measure the accuracy of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9CM) codes for bleeding and thromboembolic diagnoses.

SETTING

University affiliated, tertiary care hospital in Ottawa, Canada.

PATIENTS

A random sample of patients discharged between September 1999 and September 2000 with an ICD-9-CM code indicating a bleeding or thromboembolic diagnosis.

METHODS

Gold-standard coding was determined by a trained chart abstractor using explicit standard diagnostic criteria for bleeding, major bleeding, and acute thromboembolism. The abstractor was blinded to the original coding. We calculated the sensitivity, specificity, positive, and negative predictive values of the original ICD-9CM codes for bleeding or thromboembolism diagnoses.

RESULTS

We reviewed 616 medical records. 361 patients (59%) had a code indicating a bleeding diagnosis, 291 patients (47%) had a code indicating a thromboembolic diagnosis and 36 patients (6%) had a code indicating both. According to the gold standard criteria, 352 patients experienced bleeding, 333 experienced major bleeding, and 188 experienced an acute thromboembolism. For bleeding, the ICD-9CM codes had the following sensitivity, specificity, positive and negative predictive values [95% CI]: 93% [90-96], 88% [83-91], 91% [88-94], and 91% [87-94], respectively. For major bleeding, the ICD-9CM codes had the following sensitivity, specificity, positive and negative predictive values: 94% [91-96], 83% [78-87], 87% [83-90], and 92% [88-95], respectively. For thromboembolism, the ICD-9CM codes had the following sensitivity, specificity, positive and negative predictive values: 97% [94-99], 74% [70-79], 62% [57-68], and 98% [96-99], respectively. By selecting a sub-group of ICD-9CM codes for thromboembolism, the positive predictive value increased to 87%.

CONCLUSION

In our centre, the discharge abstract could be used to identify and exclude patients hospitalized with a major bleed or thromboembolism. If coding quality for bleeding is similar in other hospitals, these ICD-9-CM diagnostic codes could be used to study population-based warfarin-associated hemorrhagic complications using administrative databases.

Depression following Traumatic Spinal Cord Injury

OBJECTIVES

To describe the epidemiology of depression following traumatic spinal cord injury (SCI) and identify risk factors associated with depression.

METHODS

This population-based cohort study followed individuals from date of SCI to 6 years after injury. Administrative data from a Canadian province with a universal publicly funded health care system and centralized databases were used. A Cox proportional hazards model was developed to identify risk factors.

RESULTS

Of 201 patients with SCI, 58 (28.9%) were treated for depression. Individuals at highest risk were those with a pre-injury history of depression [hazard rate ratio (HRR) 1.6; 95% CI: 1.1-2.3], a history of substance abuse (HRR 1.6; 95% CI: 1.2-2.3) or permanent neurological deficit (HRR 1.6; 95% CI: 1.2-2.1).

CONCLUSION

Depression occurs commonly and early in persons who sustain an SCI. Both patient and injury factors are associated with the development of depression. These should be used to target patients for mental health assessment and services during initial hospitalization and following discharge into the community.

History of depression increases risk of type 2 diabetes in younger adults

OBJECTIVE

The purpose of this study was to assess the history of previous depression in people with incident diabetes compared with people without diabetes.

RESEARCH DESIGN AND METHODS

We conducted a population-based nested case-control study using the administrative databases of Saskatchewan Health to assess the study objective. We identified cases of type 2 diabetes based on diagnostics codes and prescription records for individuals over the age of 20 years. For each case subject, two control subjects were randomly selected from the nondiabetic population during the same index year. History of depression, based on diagnostic codes and antidepressant prescription, was ascertained up to 3 years before index date. Simple and multivariate logistic regression analysis was used to estimate the odds ratio (OR) and 95% CIs, after adjusting for age, sex, and frequency of physician visits.

RESULTS

Individuals with newly diagnosed diabetes (1,622 of 33,257; 4.9%) were 30% more likely to have had a previous history of depression compared with people without diabetes (2,279 of 59,420; 3.8%). This increased risk remained after controlling for sex and number of physician visits but was limited to subjects 20-50 years of age (adjusted OR 1.23 [95% CI 1.10-1.37]) and not in those aged > or =51 years (0.92 [0.84-1.00]).

CONCLUSIONS

Depression appears to increase the risk of developing diabetes by approximately 23% in younger adults. This provides information regarding the temporality of the relationship between diabetes and depression.

Utilization of health services following spinal cord injury: a 6-year follow-up study

STUDY DESIGN

Cohort study with 6-years follow-up.

OBJECTIVE

To describe the utilization of health services by persons with spinal cord injury (SCI) and compare it with that of the general population.

SETTING

Alberta, Canada.

METHODS

All persons who sustained an SCI in Alberta between April 1992 and March 1994 were followed from date of injury to 6 years postinjury. Cases were matched (1:5) with controls randomly selected from the general population and matched for age, gender, and region of residence. Administrative data from centralized health care databases were compiled to provide a complete picture of health care use, including hospitalizations, physician contacts, long-term care admissions, home care services, and the occurrence of secondary complications.

RESULTS

In all, 233 individuals with SCI and 1165 matched controls were followed for 6 years. Compared with the control group, persons with SCI were rehospitalized 2.6 times more often, spent 3.3 more days in hospital, were 2.7 times more likely to have a physician contact, and required 30 times more hours of home care services. Of those with SCI, 47.6% were treated for a urinary tract infection, 33.8% for pneumonia, 27.5% for depression, and 19.7% for decubitus ulcer.

CONCLUSION

SCI places a heavy burden on the health care system. Persons with SCI have greater rates of contact with the health system compared with the general population. Secondary complications continue to affect persons with SCI long after the acute trauma.

Assessing data adequacy for clinical research: reliability and validity of a surgical database

As clinical databases are utilized more frequently for clinical research, it is essential that researchers assess the quality of databased information. While researchers have begun to report strategies to measure accuracy of databased information, knowledge remains limited. The purpose of this study was to assess the reliability and validity of databased information among selected study variables contained within a computerized coronary artery surgery clinical database using the written patient medical record as an external standard. Both reliability (N = 400) and validity (N = 100) samples were randomly selected from a databased sampling frame of 548 Medicare subjects who underwent coronary artery bypass grafting surgery in 1998. Reliability assessed by consistency rates were age (95%), race (94%), gender (99%), congestive heart failure (CHF) (60.5%), angina (91.5%), renal insufficiency (82%), hypertension (91.7%), diabetes mellitus (93.7%), chronic obstructive pulmonary disease (COPD) (75.5%), clinical status (97%), American Society of Anesthesiologists classification (99%), prior peripheral vascular surgery (15.5%), prior CABGS (99%), and duration of mechanical ventilation (87.5%). These percentages reflected a large portion of missing data for CHF, COPD, and prior peripheral vascular surgery. Validity assessed by sensitivity and specificity analyses were all greater than 80%. The majority of computerized databased information among selected study variables was the same information recorded in the written patient medical record. Using the same external standard to assess both reliability and validity was a significant limitation of this study, which resulted in the same measure of data adequacy by utilizing differing statistical methods.