Assessing depression in primary care with the PHQ-9: can it be carried out over the telephone?
BACKGROUND
Telephone assessment of depression for research purposes is increasingly being used. The Patient Health Questionnaire 9-item depression module (PHQ-9) is a well-validated, brief, self-reported, diagnostic, and severity measure of depression designed for use in primary care (PC). To our knowledge, there are no available data regarding its validity when administered over the telephone.


OBJECTIVE
The aims of the present study were to evaluate agreement between self-administered and telephone-administered PHQ-9, to investigate possible systematic bias, and to evaluate the internal consistency of the telephone-administered PHQ-9.


METHODS
Three hundred and forty-six participants from two PC centers were assessed twice with the PHQ-9. Participants were divided into 4 groups according to administration procedure order and administration procedure of the PHQ-9: Self-administered/Telephone-administered; Telephone-administered/Self-administered; Telephone-administered/Telephone-administered; and Self-administered/Self-administered. The first 2 groups served for analyzing the procedural validity of telephone-administered PHQ-9. The last 2 allowed a test-retest reliability analysis of both self- and telephone-administered PHQ-9. Intraclass correlation coefficient (ICC) and weighted kappa (for each item) were calculated as measures of concordance. Additionally, Pearson's correlation coefficient, Student's t-test, and Cronbach's alpha were analyzed.


RESULTS
Intraclass correlation coefficient and weighted kappa between both administration procedures were excellent, revealing a strong concordance between telephone- and self-administered PHQ-9. A small and clinically nonsignificant tendency was observed toward lower scores for the telephone-administered PHQ-9. The internal consistency of the telephone-administered PHQ-9 was high and close to the self-administered one.


CONCLUSIONS
Telephone and in-person assessments by means of the PHQ-9 yield similar results. Thus, telephone administration of the PHQ-9 seems to be a reliable procedure for assessing depression in PC.
Pinto-Meza
Alejandra
A
Research and Development Unit, Sant Joan de Déu-SSM, Barcelona, Spain. apinto@sjd-ssm.com
Serrano-Blanco
Antoni
A
Peñarrubia
Maria T
MT
Blanco
Elena
E
Haro
Josep Maria
JM
D000328:Adult; D000368:Aged; D003863:Depression / Q000175:diagnosis*; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D013689:Telephone