Diabetes and Depression: Recognizing the Link

A growing body of evidenceclearly supports the linkbetween diabetes and depression.A meta-analysis of 39 studies ofpatients with diabetes reported an estimateof major depression in 11% ofthe patients and elevated depressivesymptoms in 31%.¹

People with diabetes have doublethe odds of having depression, comparedwith the general population.²Predictors of depression in patientswith diabetes include female sex,younger age, less education, lowerincome, smoking, obesity, and multiplediabetic complications.¹

It is important to recognize the linkbetween diabetes and depression forseveral reasons^3,4:

• Higher rates of medication nonadherencein severely depressedpatients

In addition to these problems withclinical outcomes, patients withdepression may lack support fromfamily or friends, have a negative viewof themselves, view barriers to medicationuse as overwhelming, or perceivethat the desired outcomes of treatmentwill not occur. These problemsgreatly affect patients'ability to carefor themselves and achieve the desiredoutcomes of therapy.

It is not clear the extent to which thesediseases affect each other. Depression isbelieved to decrease physical health by acombination of biological and psychologicalchanges.⁵ Psychological stress isthought to increase susceptibility to disease;persistent somatic symptoms ofdepression are thought to worsen physicalhealth over time; and depressedmood may decrease the likelihood thatpatients will seek treatment and adhereto prescribed self-care and medicationtreatment regimens. Diabetes, on theother hand, affects functional abilitybecause of the development of complications,such as vision difficulties, neuropathy,peripheral vascular disease, andlower-extremity ulcers.

Treatment of depression improvesoutcomes in patients with diabetes.Several studies have demonstratedthat patients with diabetes whoreceived medication or cognitivebehavioral therapy had improveddepression scores and improved glycemiccontrol, compared with patientswho received either a placebo or diabeteseducation alone.^6,7 In addition,treated patients achieved medicationadherence scores that were equal tothose of patients without depression.

Several approaches may be used tohelp depressed diabetic patients. Casemanagement services, which mayinclude screening for depression, mayhelp improve depression scores, perhapsthrough increased referrals to appropriatecare, but they have not been demonstratedto improve glycemic control.

Clinical pharmacists, in collaborativecare models, also have been used toimprove care in these patient populations,although specific studies evaluatingpharmacist care in depressed diabeticshave not been done. A KaiserPermanente model used clinical pharmaciststo manage medication therapyfor depression after the initial diagnosishad been established by a physician.Pharmacists documented target symptoms,identified stressors for the patient,and recommended treatment. Withinthis system, they were able to modifydosing regimens and recommend alternativetherapies if treatment failed.⁸

Pharmacist-managed diabetes clinicshave been shown to improve glycemiccontrol and adherence to the AmericanDiabetes Association guidelines for therapy.In addition to improvement inhemoglobin A^1C measurements, referralswere made more frequently for dietaryinstruction, podiatric care, and evaluationof diabetic retinopathy, comparedwith physician-managed patients.^9,10

The link between diabetes anddepression is very complicated. Healthcare costs for untreated patients maybe enormous. Treatment with appropriatemedications may significantlyimprove both psychological and physicaloutcomes. Pharmacists have theopportunity to play a significant rolein the identification and managementof patients afflicted with either or bothof these diseases.

Dr. Garrett is a clinical pharmacist practitionerat Cornerstone Health Care in HighPoint, NC.

For a list of references, send a stamped,self-addressed envelope to: ReferencesDepartment, Attn. A. Stahl, Pharmacy Times,241 Forsgate Drive, Jamesburg, NJ 08831; orsend an e-mail request to: astahl@mwc.com.