Common Conditions in Primary Care and Minimal Clinically Important Differences on Depression Scales

  • Author / Creator
    Finley, Caitlin R
  • Primary care has the highest patient volume and the greatest complexity of illness compared to other specialties and levels of health care. Although local data are available, a global perspective on the most common reasons for consulting primary care is lacking. Identifying these conditions would be helpful for directing primary care research towards patient-important priorities. Once these common conditions are determined, attention can be turned to identifying interventions that will impact patients with the conditions, as measured by patient-oriented outcomes. When describing patient-reported outcomes, it is important to report treatment effects with respect to clinical significance rather than reliance on statistical significance alone. Among conditions which are measured in scales (such as pain or depression), the minimal clinically important difference (MCID) is frequently considered to be a measure of clinical significance. The first objective of this research program was to identify what the most commonly presenting conditions in primary care are. I was also interested in whether there were differences in common reasons for visits (RFV) as reported by clinicians compared to patients, and between countries of differing economic classifications (i.e. developed compared to developing countries). A systematic review of 12 scientific databases was carried out and dual independent review was performed to select primary care studies. Studies were included if they contained ≥20,000 visits (or equivalent volume by patient-clinician interactions) and listed ≥10 RFV. Eighteen studies from 11 countries on five continents met the inclusion criteria. The 10 most common clinician-reported RFV were upper respiratory tract infection (URTI), hypertension (HTN), routine health maintenance, arthritis, diabetes, depression/anxiety, pneumonia, otitis media, back pain and dermatitis. The 10 most common patient-reported RFV were cough, back pain, abdominal symptoms, pharyngitis, dermatitis, fever, headache, leg symptoms, unspecified respiratory, and fatigue. Globally, URTI and HTN were the most common clinician-reported RFV. In developed countries, the next most common RFV were depression/anxiety and back pain, and in developing countries were pneumonia and tuberculosis. Having identified depression as the most common condition in primary care in developing countries for which MCIDs could readily be determined, the second objective of this research program was to determine the MCIDs for depression scales, and how they are derived. In particular, I aimed to develop a summary resource that provides information on depression scales and their MCIDs, for use by both researchers and those attempting to interpret the depression literature. A systematic search of the Cochrane Database of Systematic Reviews was carried out, which retrieved 80 reviews on depression. From those reviews, 1540 unique studies were identified, which contained 34 different depression scales. Estimates of MCIDs were found for 10 of the scales: Hamilton Depression Rating Scale, Montgomery Asbergs Depression Rating Scale, Beck Depression Inventory, Centre for Epidemiologic Studies Depression Scale, Zung Depression Scale, Hospital Anxiety and Depression Scale, Patient Health Questionnaire-9, Profile of Mood States, Edinburgh Postnatal Depression Scale, and Quick Inventory of Depressive Symptoms. Data were also collected on how MCIDs were determined, i.e. by using anchor-based, distribution-based, or Delphi methods. In conclusion, I found that there are differences in RFV to primary care between clinician-reported and patient-reported RFV, as well as differences in RFV between developed and developing countries. These results have utility for primary care guideline development, resource allocation, and training programs and curricula. Next steps arising from these results are for more research to be conducted on assessing common conditions, especially in developing countries. I also identified MCIDs for 10 depression scales, and their methods of derivation. These results will be helpful for clinicians to monitor depression symptoms over time and assess the effects of treatment. Suggestions arising from my findings on MCID include improved reporting of the MCID in clinical trials, and increased consistency in using depression scales.

  • Subjects / Keywords
  • Graduation date
    Fall 2017
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.