depresja w cukrzycy i leczenie.pdf

General Hospital Psychiatry 25 (2003) 158 –168

Improving primary care treatment of depression among patients with

diabetes mellitus: the design of the Pathways Study

Wayne Katon, M.D. a, *, Michael Von Korff, ScD. b , Elizabeth Lin, M.D., M.P.H. b ,

Greg Simon, M.D., M.P.H. b , Evette Ludman, Ph.D. b , Terry Bush, Ph.D. b , Ed Walker, M.D. a ,

Paul Ciechanowski, M.D., M.P.H. a , Carolyn Rutter, Ph.D. b

a Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA 98195– 6580, USA

b Center for Health Studies, Group Health Cooperative, Psychiatry Service, University Hospital, Seattle, WA 98195– 6580, USA

Abstract

This paper describes the methodology of a population based study of primary care patients with diabetes mellitus enrolled in a health

maintenance organization. The ﬁrst goal was to determine the prevalence and impact of depression in patients with diabetes. The second

goal was to randomize approximately 300 patients with diabetes and major depression and/or dysthymia in a trial to test the effectiveness

1. Introduction

Both major depression and depressive symptoms have been

shown in most studies to be associated with glucose dysregu-

lation [6 – 8]. This may either be due to the adverse impact of

depression on diabetes self-care (i.e., diet, exercise, checking

blood glucose, and taking medications), [6 – 8] direct adverse

physiologic effects on glucose metabolism, [9] or a combina-

tion of these two mechanisms. Several studies have shown that

depression is associated with poor adherence to self-care reg-

imens such as checking blood glucose, following a special diet

and medication compliance, as well as less sensitivity to insu-

lin effects on lowering blood glucose [6,10].

Two small randomized trials have shown that nortripty-

line [11] and ﬂuoxetine [12] were more efﬁcacious in con-

trolling depressive symptoms than placebo in patients with

major depression and diabetes. One cognitive behavioral

trial also demonstrated enhanced efﬁcacy compared to an

educational diabetes group [13]. One of these 3 trials found

that improved depression outcomes was associated with

improved HbA 1 C levels [13]. These three trials enrolled a

combined total of less than 180 patients and lacked power to

study key outcomes such as the effect of enhanced treatment

of depression on self-care regimens (diet, exercise, reﬁlling

medication), disability, quality of life, and medical costs.

Whether enhanced treatment of depression improves glyce-

mic control is also an unanswered question.

The study that we describe has two arms: 1) a popula-

tion-based epidemiologic investigation of the prevalence

Diabetes is a common and costly condition that affects 16

million Americans [1]. Patients with diabetes are at increased

risk of kidney disease, peripheral vascular disease, heart dis-

ease, lower extremity ulcers and amputations, retinal disease,

neuropathy, infections, digestive disease and periodontal dis-

ease [2]. The prevalence is as high as 20% in patients who are

65 years and over with signiﬁcantly higher rates in minority

group members (African Americans, Hispanics and Native

Americans) [3]. The total direct medical costs and indirect

costs in the United States due to diabetes have been estimated

at $102 billion per year [4]. Patients with diabetes appear to

have increased risk of major depression. Depression may ad-

versely affect self-care regimens as well as increase risk of

complications such as diabetic retinopathy [5–7].

Anderson and colleagues’ recent meta-analysis of the

prevalence of major depression or depressive symptoms in

patients with diabetes found a two-fold higher prevalence

rate of depression in diabetics compared to controls in 20

controlled studies [5]. Current major depression was ob-

served in 10 to 15% of diabetics with similar prevalence

rates in Type 1 and Type 2 cases [5].

* Corresponding author. Tel.: 1-206-543-7177; fax: 1-206-221-

5414.

E-mail address: wkaton@u.washington.edu (W.J. Katon).

doi:10.1016/S0163-8343(02)00013-6

W.J. Katon et al. / General Hospital Psychiatry 25 (2003) 158 –168

159

and impact of depression in patients with diabetes enrolled

in a health maintenance organization; and 2) a randomized

controlled trial to test the effectiveness of collaborative care

interventions in improving the quality of care and outcomes

of depression among patients with diabetes in primary care.

This paper describes the design of these research studies and

the rationale for key methodologic decisions. The ﬁrst part

of the Methods section will describe the recruitment for the

epidemiologic phase of the study, and the second part the

design of the randomized controlled trial.

2.2. Sample recruitment

A major methodologic issue was how to best screen and

enroll a representative sample of diabetic patients with ma-

jor depression and dysthymia. The screening was facilitated

by Group Health’s prior development of a population-based

diabetes registry. Patients are added to the diabetes registry

based on: 1) currently taking any diabetic agent; or 2) a

fasting glucose

200

also conﬁrmed by a second test within one year; or 4) a

hospital discharge diagnosis of diabetes at any time during

GHC enrollment or two outpatient diagnoses of diabetes

[15]. The goal of the epidemiologic survey was to success-

fully screen at least 4,500 primary care patients with diabe-

tes with approximately 630 expected to meet criteria for

major depression and/or dysthymia. The goal of the ran-

domized trial was to enroll approximately 300 depressed

patients in the randomized controlled trial. After consider-

ing mail versus telephone screening for depression, we

decided on mail screening as the most cost effective mech-

anism based on prior studies by members of our study group

that were able to attain 60 to 65% recruitment rates with

mail screening [7,16]. To potentially increase patient re-

sponse rates, we presented the study to each of the 9 clinics

and requested written permission from all primary care

physicians to use a stamp of their signature in the approach

letter describing the study. Among the 113 doctors, 101

(90%) agreed to allow us to use their signature stamp. For

physicians refusing to let us use their signature, we used the

name of the GHC Chief of endocrinology, Dr. David Mc-

Culloch.

Patients were screened by mail in sequential waves with

approximately 700 questionnaires sent per month. A $3 gift

certiﬁcate for a local store was included with the mailing to

encourage response. If the patient did not return a mailed

packet by 4 weeks, a second packet was sent. If this second

packet was not returned by 2 weeks, the patient received a

telephone reminder call. The ﬁrst mail-screen had a re-

sponse rate of approximately 38%, the second mailing in-

creased the response rate to 47%, and the combination of the

telephone reminder and a last mailing 6 months after the

telephone reminder increased the ﬁnal response rate to

61.7%. Figure 1 describes the recruitment and reasons for

ineligibility or refusal at each phase of the study. The study

team has received permission from the Group Health Co-

operative Institutional Review Board to collect aggregate

data on nonrespondents to ascertain whether there are dif-

ferences in demographic (age, gender) or clinical variables

(health care costs, medical comorbidity, type of diabetes or

depression treatment, and HbA 1 C levels) between respon-

dents and nonrespondents.

A major methodological question was: “What is the best

depression screening tool to use?” Ideally this screen should be

brief, easy to score and provide both a DSM-IV diagnosis and

depression severity score. We elected to use the Patient Health

2. Methods

The Pathways Study was developed by a multidisci-

plinary team in the Department of Psychiatry at the Univer-

sity of Washington and the Center for Health Studies at

Group Health Cooperative. Group Health is a nonproﬁt

health maintenance organization with 30 primary care clin-

ics in Western Washington State.

The study was funded by the National Institute of Mental

Health Services (NIMH) Division of Intervention and Ser-

vices Research. The randomized controlled trial proposed to

test the effectiveness of a collaborative care intervention

versus usual care. Collaborative care is a multimodal inter-

vention that includes integration of a “care manager” (often

a nurse or mental health specialist) into primary care. The

“care manager” works with both the patient and primary

care physician and helps with developing a shared deﬁnition

of the problem, providing patient education and support,

developing a shared focus on speciﬁc problems, targeting

goals and a speciﬁc action plan, offering support and prob-

lem-solving to optimize self-management, achieving closer

monitoring of adherence and outcomes, and facilitating ap-

pointments to the primary care physician or specialist for

patients with adverse outcomes or side-effects [14]. The

study protocol was reviewed and approved by institutional

review boards at the University of Washington and Group

Health Cooperative.

2.1. Study setting

Nine Group Health Cooperative primary care clinics in

western Washington were selected for the study. We se-

lected clinics based on 3 criteria: 1) clinics with the largest

number of diabetic patients (to save screening and interven-

tion costs; 2) clinics within a 40-mile geographic radius of

Seattle in order to decrease travel time for nurse “care

managers”; and 3) clinics with the highest percentage of

minority patients. Because minorities have higher rates of

diabetes, we were able to enroll substantial numbers of

minority patients even though the general population was

predominantly Caucasian.

126 conﬁrmed by a second out-of-range

test within one year; or 3) a random plasma glucose

160

W.J. Katon et al. / General Hospital Psychiatry 25 (2003) 158 –168

Fig. 1. Recruitment of epidemiologic study and randomized controlled trial.* Eligibility criteria: PHQ 10 or greater.** Patients were categorized as

“Ineligible – Other” if: 1) they were enrolled in another study; 2) their spouse was enrolled in PATHWAYS; 3) they were high risk for self-harm or if they

refused a self-harm assessment; or 4) there were other special circumstances (i.e., – there was one case where the team deemed someone ineligible due to

a recent hospitalization for drug overdose).

Questionnaire (PHQ) based on this questionnaire’s ability to

provide both a dichotomous diagnosis of major depression as

well as a continuous severity score [17]. The PHQ diagnosis of

major depression has been found to have high agreement with

the diagnosis of major depression based on structure psychi-

atric interview [17]. Because we were also interested in the

DSM-IV diagnosis of dysthymia, which is not included in the

PHQ, we added questions from the NIMH Diagnostic Inter-

view Schedule [18] on dysthymia.

2.3. Methodology of the Pathways randomized controlled

trial

10 on the

initial PHQ in the mail screen, which has been found to be

the optimal cut-point in screening for major depression [17]

We required patients to have a second screen by telephone

about two weeks after scoring 10 or greater on the PHQ. On

this second screen, patients were required to have persistent

Patients were required to have a score of

W.J. Katon et al. / General Hospital Psychiatry 25 (2003) 158 –168

161

1.1. Double-screening eliminates those with tran-

sient or spontaneously resolving depression. A total of 348

patients were excluded based on an SCL

on the intervention developed for the IMPACT Study,

which randomized 1801 elderly primary care depressed

patients to a nurse collaborative intervention or usual care

[21]. A key design question for the team was: “Would this

intervention be designed to enhance treatment of depression

only, or to improve quality of care for both depression and

diabetes?” We elected to design an intervention to improve

quality of care and outcomes of depression but to not di-

rectly intervene to improve diabetes education or care, ex-

cept to the extent that addressing diabetes care issues arose

in the context of treating depression. An example of a

diabetes issue that could have been addressed in problem

solving therapy would be if the patient chose lack of exer-

cise or having problems with diet as a problem she or he

wanted to work on. By improving depression care, we could

then test effects of improved depression outcomes on dia-

betes self-care (diet, exercise, medication adherence), and

glycemic control.

Efﬁcacy studies often ask questions such as “Is this

antidepressant more effective than placebo?” The health

services question for this effectiveness study was: “Is an

innovative method to improve service delivery that provides

guideline level antidepressant treatment or brief psychother-

apy more effective than usual care?” In developing this

intervention, we tried to optimize patient recruitment and

retention by providing an initial choice based on patient

preference of either antidepressant medication or problem

solving therapy (PST). It is controversial whether providing

patient choice of treatment leads to better outcomes, [22]

but choice is more like “real world” treatment decisions that

physicians and patients negotiate. We expected choice to

enhance recruitment and retention of patients. Choice of

treatment is also consistent with the Institute of Medicine’s

emphasis on understanding patients’ beliefs and preferences

in negotiating a treatment plan [23]. Problem solving ther-

apy was chosen because it is patient-centered, brief and

well-accepted by primary care patients due to its psycho-

educational content. Problem solving therapy has been

found to be as effective in randomized trials in primary care

as antidepressants in improving depressive symptoms of

patients with major depression [24]. It was also easier to

train Depression Care Specialists in providing PST than

other forms of psychotherapy.

1.1.

To recruit a representative sample, we had few medical

or psychiatric exclusions. We elected to include diabetics

who were already receiving antidepressant medication or

psychotherapy from nonpsychiatrist clinicians, but who still

had high depression scores. This decision was based on

prior ﬁndings that showed that many primary care patients

with depression are exposed to antidepressants at lower than

guideline-recommended dosage and duration [20]. Eligible

patients were ambulatory, English-speaking, with adequate

hearing to complete a telephone interview, and planned to

continue to be enrolled in GHC over the next year. Psychi-

atric exclusions were: 1) currently in care by, or scheduled

to see, a psychiatrist; 2) a diagnosis based on Group

Health’s automated diagnostic data of bipolar disorder or

schizophrenia; 3) use of antipsychotic or mood stabilizer

medication based on Group Health’s automated pharmacy

in the prior year; and 4) mental confusion on the interview

suggesting signiﬁcant dementia (Fig. 1).

2.4. Randomization

After completion of the baseline telephone interview and

verbal informed consent, participants were informed that

they would be randomly assigned to the Intervention or

Usual Care group through a computer generated number.

Patients were told that if they were assigned to the Inter-

vention group a nurse would call them within one week to

set up an appointment. If they were assigned to the Usual

Care group they would receive a mailed written informed

consent for telephone follow-up calls and HbA 1 C blood

draws to sign and mail back, and the ﬁrst telephone survey

call in three months.

After the baseline telephone call, the research assistant

handed a face sheet with a study identiﬁcation number to the

project coordinator to put in an Access data base. The

Access data base then automatically generated a random

assignment number which indicated whether patients were

in the Intervention or Usual Care group. Randomization

allocation occurred in blocks of eight. For those patients in

the intervention group, the computer generated a face sheet

with a patient name and phone number that the project

coordinator delivered to the nurses. For both Intervention

and Usual Care patients the computer then added the patient

identiﬁcation data to the telephone survey data base with the

speciﬁc dates for the series of follow-up interviews.

2.6. What type of professional should be trained as a

Depression Care Specialist (DCS)?

Given the need for the DCS to be proﬁcient in medica-

tion management and PST, to have experience working with

patients with one or more chronic medical illnesses, and to

be comfortable working in a primary care setting, we chose

registered nurses to implement collaborative care treatment.

Registered nurses at GHC were already providing disease

management for diabetes and congestive heart failure.

Therefore, this model would have a greater chance to be

2.5. Intervention design

The intervention was an individualized, stepped care

depression treatment program provided by a Depression

Clinical Specialist (DCS) nurse in collaboration with the

primary care physician. This intervention design was based

symptoms by having an SCL-20 depression [19] mean item

score of

162

W.J. Katon et al. / General Hospital Psychiatry 25 (2003) 158 –168

integrated into the GHC plans for improving disease man-

agement of depression after the study.

We also required a registered nurse (R.N.) degree, not a

nurse practitioner (ARNP), since primary care physicians

would continue to prescribe and this level of training is

more generalizable and cost-effective.

We hired three half-time registered nurses. They each

covered two to four primary care clinics, that were geo-

graphically as far as 25 miles apart, with case loads of 40 to

65 patients each once the study was fully underway.

nurse had supervision twice a month with a team of a

psychiatrist, psychologist (on PST) and family physician to

review new cases and patient progress. Nurses interacted

regularly (via written notes and verbally) with the primary

care physician treating the patient. On alternative weeks,

nurses reviewed cases by telephone with the psychiatrist

supervisor. The psychiatrist supervisor regularly reviewed

choices and dosages of medication and clinical response,

and recommended changes, which the nurse discussed with

the primary care physician and patient.

A unique clinical monitoring system was developed us-

ing Pendragon software [28] for a hand-held organizer for

the nurses to enter tracking data after each patient contact

including initial PHQ score, initial date of intake, last date

seen and last PHQ score, whether the patient has had a 50%

decrease in PHQ score by 12 weeks, initial treatment (PST

or antidepressants), current treatment and number of outpa-

tient and telephone contacts. This monitoring system al-

lowed nurses and supervisors to easily check which patients

were due for telephone or in-person follow-up visits. Each

week these data were transferred to an Access ﬁle and an

updated printout of all cases was used in weekly supervi-

sion. This facilitated each supervisor’s review of the process

and outcomes of care for the large number of cases being

managed.

The printout included an asterisk for cases that had not

decreased 50% or more on the PHQ at 10 weeks. Supervi-

sion started on new cases, progressed to asterisked cases and

then to cases in initial phases of treatment.

2.7. Training

Nurses received an initial one-week training course on

diagnosis and pharmacotherapy and an introduction to prob-

lem solving treatment methods. A psychiatrist, primary care

physician and psychologist participated in training. An in-

tervention manual from the IMPACT trial [25] was used to

train nurses on collaborative care, stepped care principles,

pharmacology and problem solving approaches.

Nurses were also trained using the manual for PST-PC

[26] during a training period following the protocol de-

scribed by Hegel and colleagues [27]. Formal training in-

cluded didactics, role play, observation of a videotaped

demonstration, and review of the treatment manual. Each

nurse was required to treat at least 4 depressed patients with

6 sessions of PST-PC over a 2-month period. Each session

was audiotaped, and sessions 1, 3 and 5 were rated using

Hegel’s PST Adherence and Competency Rating Scale [27].

Nurses were required to meet the criteria of at least 3 tapes

from each of two different patients’ audiotaped treatment

sessions being rated satisfactory by the team psychologist

(Dr. Ludman). During the training period, the nurses met

weekly with the psychologist for review of the audiotaped

sessions. During the course of the study, the nurses met

regularly with the psychologist to review audiotapes and

speciﬁc clinical problems arising in PST sessions. Group

supervision sessions were held weekly or twice a month for

the ﬁrst months of the study, reducing in frequency over

time. During the second year, group supervision occurred

monthly. Individual PST-PC supervision sessions with

nurses occurred on an as-needed basis for review of difﬁcult

sessions.

2.9. Stepped care algorithm

50% decrease in severity based on the PHQ)

10 to12 weeks after Step 1 level treatment with either PST

or antidepressant medication, they could either: a) switch to

a second antidepressant with a different mechanism or side-

effect proﬁle; b) switch to the alternative treatment (from

PST to medication or vice versa); or c) receive augmenta-

tion of PST or antidepressant medication with the ﬁrst

treatment they had received. This change in treatment at 10

to 12 weeks was labeled Step 2 care. Another option in Step

2 was a psychiatric consultation to evaluate treatment op-

tions. For patients who received one or more Step 2 inter-

ventions, persistent symptoms (

2.8. Collaborative care

A team of clinicians delivered the treatment for interven-

tion patients. Nurses carried out the majority of treatment

that included an initial one hour visit followed by twice a

month, half-hour appointments (telephone and in-person) in

the acute phase of treatment (0 to 12 weeks). The ﬁrst

appointment included a semistructured biopsychosocial his-

tory, patient education, development of the therapeutic al-

liance, understanding the patient explanatory model of ill-

ness and negotiation whether to start treatment with an

antidepressant medication or problem solving therapy. Each

50% improvement) and

lack of patient and clinician satisfaction with outcome after

a second treatment (8 to 12 weeks) could lead to referral to

the Group Health Cooperative (GHC) mental health system

for longer term follow-up including management by a psy-

chiatrist (Step 3).

A stepped care approach was used in which different

patients received different intensity of services based on

their observed outcome (Table 1). Stepped care recognizes

that patients have marked differences in psychiatric and

medical comorbidity as well as differences in response to

antidepressant medication and/or psychotherapy [29]. In the

Pathways trial if patients still had persistent depressive

symptoms (

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