Improving ambulatory saliva-sampling compliance in pregnant women: a randomized controlled study.
OBJECTIVE
Noncompliance with scheduled ambulatory saliva sampling is common and has been associated with biased cortisol estimates in nonpregnant subjects. This study is the first to investigate in pregnant women strategies to improve ambulatory saliva-sampling compliance, and the association between sampling noncompliance and saliva cortisol estimates.


METHODS
We instructed 64 pregnant women to collect eight scheduled saliva samples on two consecutive days each. Objective compliance with scheduled sampling times was assessed with a Medication Event Monitoring System and self-reported compliance with a paper-and-pencil diary. In a randomized controlled study, we estimated whether a disclosure intervention (informing women about objective compliance monitoring) and a reminder intervention (use of acoustical reminders) improved compliance. A mixed model analysis was used to estimate associations between women's objective compliance and their diurnal cortisol profiles, and between deviation from scheduled sampling and the cortisol concentration measured in the related sample.


RESULTS
Self-reported compliance with a saliva-sampling protocol was 91%, and objective compliance was 70%. The disclosure intervention was associated with improved objective compliance (informed: 81%, noninformed: 60%), F(1,60)  = 17.64, p<0.001, but not the reminder intervention (reminders: 68%, without reminders: 72%), F(1,60) = 0.78, p = 0.379. Furthermore, a woman's increased objective compliance was associated with a higher diurnal cortisol profile, F(2,64)  = 8.22, p<0.001. Altered cortisol levels were observed in less objective compliant samples, F(1,705)  = 7.38, p = 0.007, with delayed sampling associated with lower cortisol levels.


CONCLUSIONS
The results suggest that in pregnant women, objective noncompliance with scheduled ambulatory saliva sampling is common and is associated with biased cortisol estimates. To improve sampling compliance, results suggest informing women about objective compliance monitoring but discourage use of acoustical reminders.
University of Basel, Department of Psychology, Division of Clinical Psychology and Epidemiology, Basel, Switzerland ; Diagnostic and Crisis Intervention Centre, Department of Psychiatry, University of Basel, Basel, Switzerland.
Julian
J
Moeller
University of Basel, Department of Psychology, Division of Clinical Psychology and Epidemiology, Basel, Switzerland.
Roselind
R
Lieb
University of Basel, Department of Psychology, Division of Clinical Psychology and Epidemiology, Basel, Switzerland.
Andrea H
AH
Meyer
Department of Obstetrics, University Hospital Zurich, Zurich, Switzerland.
Katharina Quack
KQ
Loetscher
National Centre of Competence in Research (NCCR), Swiss Etiological Study of Adjustment and Mental Health (sesam), University of Basel, Basel, Switzerland.
Bettina
B
Krastel
University of Basel, Department of Psychology, Division of Clinical Psychology and Epidemiology, Basel, Switzerland ; National Centre of Competence in Research (NCCR), Swiss Etiological Study of Adjustment and Mental Health (sesam), University of Basel, Basel, Switzerland ; Faculty of Medicine, Ruhr-University Bochum, Bochum, Germany.
Gunther
G
Meinlschmidt
D000328:Adult; D000553:Ambulatory Care; D015415:Biomarkers; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D010342:Patient Acceptance of Health Care; D011247:Pregnancy; D012463:Saliva / Q000378:metabolism*; D057566:Self Report; D013048:Specimen Handling; D013315:Stress, Psychological / Q000453:epidemiology / Q000378:metabolism
D015415:Biomarkers; D006854:Hydrocortisone