Effectiveness of a supportive telephone counseling intervention in type 2 diabetes patients: randomized controlled study

PLoS One. 2013 Oct 30;8(10):e77954. doi: 10.1371/journal.pone.0077954. eCollection 2013.


Objectives: This randomized controlled trial investigated whether a patient-centered supportive counseling intervention comprising monthly telephone-based counseling sessions by practice nurses over 12 months improved diabetes-related medical and psycho-social outcomes above usual care in type 2 diabetes patients with poor glycemic control at baseline (HbA1c >7.5%) in a primary care setting.

Research design: Patients were individually randomized into intervention (n = 103) and usual care group (n = 101). The primary outcome was change in HbA1c-concentration after 12 and 18 months. Secondary outcomes were lipid levels, blood pressure, health-related quality of life and symptoms of depression. Follow-up-measurements were carried out after 6, 12 and 18 months to assess potential immediate and maintained effects of the intervention. For the multivariate analysis, hierarchical linear models were computed for each outcome to assess within-group changes in outcomes over time and between-group differences in patterns of change.

Results: HbA1c (in %) decreased significantly from baseline to 12-month follow-up measurement both in the intervention (-0.44) and the usual care group (-0.51), but there was no significant between-group intervention effect. Significant improvements in the intervention group along with significant between-group differences were seen for health-related quality of life and, transiently, for systolic blood pressure and depression.

Conclusions: Although we found no beneficial effect of the supportive telephone counseling in terms of a reduction of HbA1c above usual care, our findings suggest some beneficial effects on cardiovascular risk factors, quality of life and depression. Continuous efforts might be needed to sustain improvements in patient outcomes.

Trial registration: ClinicalTrials.gov NCT00742547.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Counseling / methods*
  • Depression / prevention & control*
  • Diabetes Mellitus, Type 2 / therapy*
  • Female
  • Glycated Hemoglobin / analysis
  • Humans
  • Male
  • Prospective Studies
  • Quality of Life*
  • Telephone*


  • Glycated Hemoglobin A

Associated data

  • ClinicalTrials.gov/NCT00742547

Grants and funding

This study was supported by a grant of the German Federal Ministry of Education and Research (01GX0746). The funding body had no role in the study design, the collection, analysis or interpretation of the data, the writing of the manuscript, or on the decision to submit the paper for publication.