Measuring depression levels in HIV-infected patients as part of routine clinical care using the nine-item Patient Health Questionnaire (PHQ-9)

Patient Health Questionnaire: Greek language validation and subscale factor structure

This study aimed to assess the reliability, validity, and factor structure of the Greek translation of the Patient Health Questionnaire (PHQ) in a sample of Cypriot, Greek-speaking university students. This is the first study to examine PHQ psychometric properties in Greek and to investigate the factor structure of the PHQ subscales. A total of 520 participants (73.9% women; M(Age) = 21.57; SD, 4.94) completed the PHQ and assessment tools used for convergent validity analysis. Patient Health Questionnaire was translated and culturally adapted according to international standards. Overall, PHQ subscales in Greek language demonstrated good internal consistency (mean Cronbach α = .75, P < .001) and convergent validity with the following: Alcohol Use Disorders Identification Test, Beck Depression Inventory, Psychiatric Diagnostic Screening Questionnaire (panic disorder, somatization, bulimia, and binge eating), and Anxiety Sensitivity Index (overall mean, r = 0.52; P < .001). The relation between the PHQ subscale diagnoses and functional impairment, as assessed by the 12-item Health Survey 12, was comparable with the original validation results for all subscales except alcohol. The depression, alcohol, and anxiety subscales exhibited single-factor structures. Subscales assessing eating disorders, panic disorder, and somatization difficulties exhibited 2-, 3-, and 4-factor structures, respectively. Overall, PHQ subscales demonstrated good psychometric properties, with the exception of the subscale examining problematic alcohol use. Overall, PHQ demonstrates good reliability, validity, and appropriate factor structure in a Greek-speaking college population. Psychometric research is needed on the Greek PHQ in primary care settings.

Modifying measures based on differential item functioning (DIF) impact analyses

OBJECTIVE

Measure modification can impact comparability of scores across groups and settings. Changes in items can affect the percent admitting to a symptom.

METHODS

Using item response theory (IRT) methods, well-calibrated items can be used interchangeably, and the exact same item does not have to be administered to each respondent, theoretically permitting wider latitude in terms of modification.

RESULTS

Recommendations regarding modifications vary, depending on the use of the measure. In the context of research, adjustments can be made at the analytic level by freeing and fixing parameters based on findings of differential item functioning (DIF). The consequences of DIF for clinical decision making depend on whether or not the patient's performance level approaches the scale decision cutpoint. High-stakes testing may require item removal or separate calibrations to ensure accurate assessment.

DISCUSSION

Guidelines for modification based on DIF analyses and illustrations of the impact of adjustments are presented.

A computerized adaptive version of the SF-36 is feasible for clinic and Internet administration in adults with HIV

DYNHA SF-36 is a computerized adaptive test version of the SF-36 Health Survey. The feasibility of administering a modified DYNHA SF-36 to adults with HIV was evaluated with Johns Hopkins University Moore (HIV) Clinic patients (N=100) and Internet consumer health panel members (N=101). Participants completed the DYNHA SF-36, modified to capture seven health domains [(physical function (PF), role function (RF, without physical or emotional attribution), bodily pain (BP), general health, vitality (VT), social function (SF), mental health (MH)], and scored to produce two summary components [Physical Component Summary (PCS), Mental Component Summary (MCS)]. Item-response theory-based response consistency, precision, mean scores, and discriminant validity were examined. A higher percentage of Internet participants responded consistently to the DYNHA SF-36. For each domain, three standard deviations were covered with five items (90% reliability); however, RF and SF scores were less precise at the upper end of measurement (better functioning). Mean scores were slightly higher for the Internet sample, with the exception of VT and MCS. Clinic and Internet participants reporting an AIDS diagnosis had significantly lower mean PCS and PF scores than those without a diagnosis. Additionally, significantly lower RF and BP scores were found for Internet participants reporting an AIDS diagnosis. The measure was well accepted by the majority of participants, although Internet respondents provided lower ratings for the tool's usefulness. The DYNHA SF-36 has promise for measuring the impact of HIV and its treatment in both the clinic setting and through telemonitoring.

HIV-associated neurocognitive disorders (HAND) in a South Asian population - contextual application of the 2007 criteria

OBJECTIVES

To estimate the prevalence of HIV-associated neurocognitive disorders (HAND) among HIV patients in a multiethnic South Asian population, describe the pattern of neurocognitive impairment in HAND and the factors associated with HAND.

DESIGN

A cross-sectional survey of HIV-positive outpatients and inpatients.

SETTING

The sole referral centre for HIV/AIDS treatment in Singapore.

PARTICIPANTS

Inclusion criteria were HIV positive, age between 21 and 80 years old and at least 3 years of education. Exclusion criteria included concomitant delirium, serious systemic disease or major psychiatric illness. 265 patients did not meet criteria or declined to participate. The final sample size was 132.

OUTCOME MEASURES

The primary outcome measure was cognitive impairment based on performance on the Montreal Cognitive Assessment, International HIV Dementia Scale and Instrumental Activities of Daily Living. The secondary outcome measure was the classification of impairment based on the 2007 updated research nosology for HAND.

RESULTS

The prevalence of HAND was 22.7% of which 70% (15.9% of total) were asymptomatic neurocognitive impairment, 23.3% (5.3% of total) were mild neurocognitive disorder and 6.7% (1.5% of total) were HIV-associated dementia. Increasing age (OR 1.104, 95% CI 1.054 to 1.155, p<0.001), less education (OR 0.78, 95% CI 0.69 to 0.89, p<0.001) and low baseline CD4 count (OR 0.15, 95% CI 0.03 to 0.74, p=0.019) were associated with HAND. Delayed recall, language and abstract thinking were the domains most commonly affected, but impairment in visuospatial ability (RC 3.013, 95% CI 1.954 to 4.073, p<0.001) and attention (RC 2.205, 95% CI 1.043 to 3.367, p<0.001) were most strongly associated with HAND.

CONCLUSION

HAND is common among HIV patients in a South Asian sample, most of whom are asymptomatic. Older patients with less education and severe illness at diagnosis are at highest risk of HAND. Delayed recall is most commonly affected, but visuospatial dysfunction is most strongly associated with prevalent HAND.

Migrating from a legacy fixed-format measure to CAT administration: calibrating the PHQ-9 to the PROMIS depression measures

PURPOSE

We provide detailed instructions for analyzing patient-reported outcome (PRO) data collected with an existing (legacy) instrument so that scores can be calibrated to the PRO Measurement Information System (PROMIS) metric. This calibration facilitates migration to computerized adaptive test (CAT) PROMIS data collection, while facilitating research using historical legacy data alongside new PROMIS data.

METHODS

A cross-sectional convenience sample (n = 2,178) from the Universities of Washington and Alabama at Birmingham HIV clinics completed the PROMIS short form and Patient Health Questionnaire (PHQ-9) depression symptom measures between August 2008 and December 2009. We calibrated the tests using item response theory. We compared measurement precision of the PHQ-9, the PROMIS short form, and simulated PROMIS CAT.

RESULTS

Dimensionality analyses confirmed the PHQ-9 could be calibrated to the PROMIS metric. We provide code used to score the PHQ-9 on the PROMIS metric. The mean standard errors of measurement were 0.49 for the PHQ-9, 0.35 for the PROMIS short form, and 0.37, 0.28, and 0.27 for 3-, 8-, and 9-item-simulated CATs.

CONCLUSIONS

The strategy described here facilitated migration from a fixed-format legacy scale to PROMIS CAT administration and may be useful in other settings.

Somatic symptoms and the association between hepatitis C infection and depression in HIV-infected patients

Studies of depression and hepatitis C virus (HCV) infection in HIV-infected patients have been contradictory and often not addressed key differences between HCV-infected and uninfected individuals including substance use. This cross-sectional observational study from the University of Washington HIV cohort examined associations between HCV, symptoms, and depression in HIV-infected patients in routine clinical care. Patients completed instruments measuring depression, symptoms, and substance use. We generated depression severity scores and used linear regression to examine the relationship with HCV accounting for demographic and clinical characteristics. We conducted sensitivity analyses in which we removed depression somatic symptom items (e.g., fatigue) from depression scores, and sensitivity analyses in which we also adjusted for nondepression somatic symptom items to examine the role of somatic and nonsomatic symptoms in the association between depression and HCV. Of 764 HIV-infected patients, 160 (21%) were HCV-infected. In adjusted analysis, HCV-infected patients had worse depression severity (p =0.01) even after adjusting for differences in substance use. HCV remained associated with depression severity in secondary analyses that omitted the depression somatic patient health questionnaire-9 (PHQ-9) items (p=0.01). However, when nondepression somatic symptoms were included as covariates in multivariate analyses, HCV was no longer associated with depression (p=0.09).

Multiple, correlated covariates associated with differential item functioning (DIF): Accounting for language DIF when education levels differ across languages

Differential item functioning (DIF) occurs when a test item has different statistical properties in subgroups, controlling for the underlying ability measured by the test. DIF assessment is necessary when evaluating measurement bias in tests used across different language groups. However, other factors such as educational attainment can differ across language groups, and DIF due to these other factors may also exist. How to conduct DIF analyses in the presence of multiple, correlated factors remains largely unexplored. This study assessed DIF related to Spanish versus English language in a 44-item object naming test. Data come from a community-based sample of 1,755 Spanish- and English-speaking older adults. We compared simultaneous accounting, a new strategy for handling differences in educational attainment across language groups, with existing methods. Compared to other methods, simultaneously accounting for language- and education-related DIF yielded salient differences in some object naming scores, particularly for Spanish speakers with at least 9 years of education. Accounting for factors that vary across language groups can be important when assessing language DIF. The use of simultaneous accounting will be relevant to other cross-cultural studies in cognition and in other fields, including health-related quality of life.

Challenges in addressing depression in HIV research: assessment, cultural context, and methods

Depression is one of the most common co-morbidities of HIV infection. It negatively impacts self-care, quality of life, and biomedical outcomes among people living with HIV (PLWH) and may interfere with their ability to benefit from health promotion interventions. State-of-the-science research among PLWH, therefore, must address depression. To guide researchers, we describe the main diagnostic, screening, and symptom-rating measures of depression, offering suggestions for selecting the most appropriate instrument. We also address cultural considerations in the assessment of depression among PLWH, emphasizing the need to consider measurement equivalence and offering strategies for developing measures that are valid cross-culturally. Finally, acknowledging the high prevalence of depression among PLWH, we provide guidance to researchers on incorporating depression into the theoretical framework of their studies and employing procedures that account for participants with depression.

lordif: An R Package for Detecting Differential Item Functioning Using Iterative Hybrid Ordinal Logistic Regression/Item Response Theory and Monte Carlo Simulations

Logistic regression provides a flexible framework for detecting various types of differential item functioning (DIF). Previous efforts extended the framework by using item response theory (IRT) based trait scores, and by employing an iterative process using group-specific item parameters to account for DIF in the trait scores, analogous to purification approaches used in other DIF detection frameworks. The current investigation advances the technique by developing a computational platform integrating both statistical and IRT procedures into a single program. Furthermore, a Monte Carlo simulation approach was incorporated to derive empirical criteria for various DIF statistics and effect size measures. For purposes of illustration, the procedure was applied to data from a questionnaire of anxiety symptoms for detecting DIF associated with age from the Patient-Reported Outcomes Measurement Information System.