Screening for Depression

Clinical Question

Are screening tools for depression effective in primary care practice?

Evidence-Based Answer

Sensitive and specific screening tools and effective treatments are available for depression. However, screening for depression has not been shown to increase the number of patients who receive treatment or to improve patient outcomes. This may be because the positive predictive values of screening tests for depression are lower in primary care, or because physicians already are adept at identifying those patients most likely to benefit from treatment (i.e., those who have the most severe symptoms and the greatest functional limitations).

Practice Pointers

There is evidence to suggest that depression is underrecognized in primary care and that patients who are depressed use health care resources more frequently. Therefore, improving care for patients with depression has the potential to improve outcomes and lower costs. A number of validated screening tools have been developed to identify patients with depression in primary care, but research has found mixed results on clinical outcomes.1 In 2002, the U.S. Preventive Services Task Force (USPSTF) found at least fair evidence to recommend that adults should be screened for depression in clinical practices that have systems in place to ensure accurate diagnosis, effective treatment, and follow-up.2 Clinical outcomes are better when the screening is followed up with treatment. The USPSTF did not find data to help physicians design effective diagnosis, treatment, and follow-up procedures.

Gilbody and colleagues revisited this topic in 2005. They searched the literature for randomized controlled trials of screening instruments for depression in primary care settings and found 12 studies with a total of 5,693 patients. Overall, they found that using a screening instrument only slightly increased the detection of depression (relative risk, 1.38; 95% confidence interval, 1.04 to 1.83). However, the results were heterogeneous. There was an insignificant trend toward increased intervention when screening instruments were used. Furthermore, three out of four studies showed patients who were screened had no difference in clinical outcome. No studies on cost-effectiveness were found. It is possible that an enhanced model of care for follow-up on screening results may improve outcomes. However, no studies included follow-up with enhanced models of care such as case management or collaborative care.

Until models of care are developed that improve health care outcomes for patients with depression, family physicians should spend their limited time on other interventions. Unstructured observation by physicians may be sufficient to identify those patients with significant functional limitations who will benefit the most from treatment.

Dietary Advice to Lower Cardiovascular Risk

Clinical Question

Does dietary advice to patients achieve sustained dietary change or improvements in cardiovascular risk profile?

Evidence-Based Answer

Dietary advice to lower fat and salt intake and increase intake of fruits, vegetables, and fiber produces modest improvements in cardiovascular risk factors. More intensive counseling yields greater effects.

Practice Pointers

Weight loss of 4 to 8 percent of body weight is associated with a decrease in blood pressure of 3 mm Hg (systolic and diastolic) and may decrease the need for medication in patients with hypertension.1 Salt reduction lowers blood pressure,2 and a low-fat diet can reduce cardiovascular risk.3 Obesity is associated with a variety of poor health outcomes. However, it is not clear whether dietary advice alone is enough to help patients make healthy eating choices that could prevent or delay the onset of disease.

Brunner and colleagues searched for randomized trials comparing dietary advice with no advice for the improvement of cardiovascular risk factors or for achieving sustained dietary changes in healthy adults. They found 23 trials with a total of 24,443 patients. The intervention arms consisted predominantly of individual counseling, group sessions, or written advice to lower fat and salt intake while increasing fruit, vegetable, and fiber intake. The least intensive interventions were single encounters. The most intensive included 50 hours of counseling over four years. Patients were followed for three months to four years with a median duration of nine months.

In the four trials that reported on blood pressure, dietary advice resulted in non-significant reductions of 2.1 mm Hg in systolic blood pressure and 1.6 mm Hg in diastolic blood pressure. Seven trials of dietary advice reported total blood cholesterol; these showed a statistically significant mean reduction in low-density lipoprotein cholesterol of 5 mg per dL (0.13 mmol per L) with no effect on high-density lipoprotein cholesterol or triglycerides. The 10 studies that measured dietary fat showed a mean reduction of 6 percent in the total dietary fat intake as a percentage of total calories. In eight studies, dietary advice increased patient intake of fruits and vegetables by 1.2 servings per day. Four studies showed that advising patients to increase dietary fiber led to a mean increase in fiber intake of 7.2 g per day. More intensive interventions tended to have greater effects. Based on their findings, the authors estimate that dietary advice may reduce the incidence of coronary heart disease by 12 percent.

The National Heart, Lung, and Blood Institute has a variety of resources for dietary advice available online. Patients who want to learn about healthy lifestyles can visit http://www.nhlbi.nih.gov/health/index.htm#tools. Among the resources available at the Web site are a body mass index calculator, a Portion Distortion quiz, an interactive menu planner, recipes, and general and disease-specific dietary advice.