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We hypothesized that somatizing patients managed by primary care physicians (PCP) would improve with a relationship-based intervention.
We randomized 30 adults with medically unexplained symptoms to treatment or usual care. Four PCPs were trained to intervene with cognitive-behavioral, pharmacological, and patient-centered management and deployed the intervention with seven scheduled visits over 12 months. Outcomes obtained at baseline and 12 months were: Mental component summary (MCS), the primary endpoint, and measures of physical and psychological symptoms and of satisfaction with the PCP.
Patients averaged 52.5 years; 83.3% were female; 79.6% were black. Using a difference of differences approach, we found that the intervention produced a large effect size (ES) (0.82; CI: 0.08 to 1.57) for the MCS in the predicted direction, similar to the ES for physical (−0.80; CI: −1.55 to −0.04) and psychological (−1.06; CI: −1.83 to −0.28) improvement and for increased satisfaction with the PCP (0.94; CI: 0.15 to 1.74). Using ANCOVA in a sensitivity analysis, we found that the ES fell slightly (0.59), while other measures were unchanged.
Moderate-large effect sizes support the hypothesis that PCPs can effectively treat somatization. This points to the importance of performing a full RCT.
Patients with somatization are common and have physical symptoms with little documented basis in disease1. The prevalence of primary care patients with one or more somatizing symptoms ranges from 33% upwards in outpatient settings, and their care has occasioned safety and cost problems1. We recently demonstrated that nurse practitioners (NP) achieved clinically significant improvement following a 12-month intervention for distressed, high-utilizing patients with medically unexplained symptoms (MUS)1,2. However, treatment of MUS by primary care providers has been infrequent and the results are mixed3–6. Not using the cognitive-behavioral treatment (CBT) and antidepressants we used, two studies had no impact on outcomes3,5, while the other showed a decrease in symptoms6, according to a recent review of RCTs for treatment of somatoform disorders4.
This brief report describes a pilot study of MUS treated by primary care physicians (PCP) assisted by a case manager (CM) with an intervention similar to our previous one using NPs.
All 19 providers at the two sites agreed that their patients participate. HFHS research team members then called each patient, and subjects who agreed were then further screened with the MH to exclude less severe subjects.
Of 82 eligible subjects, 44 were interested (54%); 79.6% were African Americans. Of these, 30 were recruited (68%) and followed at one or more post-baseline interviews (15 Treatment and 15 UC). There were 73% females in Treatment and 93% in UC, with an average age of 52.5 years in each group.
At baseline, shown in Table 1, treatment patients had significantly greater deficits on the MCS (p=0.02), perhaps due to somewhat higher depressive symptoms (CES-D). Treatment and UC control patients were comparable on other measures.
Shown also in Table 1, an effect size (ES) in the large range (0.82; CI: 0.08 to 1.57) occurred in the predicted direction for the MCS. The intervention also had large effect sizes in the predicted direction for supplementary measures including PHQ-15 (−0.80; CI: −1.55 to −0.04), CES-D (−1.06; CI: −1.83 to −0.28), and SQ-1 (0.94; CI: 0.15 to 1.74). The DID for CES-D was statistically significant (p=0.03), and approached significance for MCS (p=0.08), PHQ-15 (p=0.09), and SQ-1 (p=0.05). To evaluate regression to the mean, a standard ANCOVA yielded a smaller but still impressive ES of 0.59 for MCS; there were no substantive ES changes for other measures on ANCOVA.
Following Chuang-Stein & Tong20, we evaluated the magnitude of regression to the mean (RTM). The adjustment for RTM may be particularly relevant for MCS and CES-D because one of the exclusion criteria in our trial is non-severe MUS, defined as the MH subscale of the SF-36 being greater than 77. The standard ANCOVA adjustment for RTM partials out the baseline differences in outcomes. Such adjustment yielded a treatment effect of 4.6 for MCS and −8.5 for CES-D, with DID estimates of 12.7 and −15.3, respectively. For all other outcomes, the RTM effects were not very large. Thus there was still a substantive treatment effect after eliminating the RTM effects.
To evaluate the impact of the CM, we compared the nine non-CM intervention cases to the control group. The difference in difference score for MCS was reduced to 3.8 points, suggesting that the CM made a contribution to the strength of the intervention. For CES-D, the difference in difference score remained approximately the same (−15.8 points).
Table 2 summarizes key data about the PCPs’ process of care.
In a small trial using PCPs to manage somatizing patients, we found moderate to large effect sizes for better mental functioning accompanied by improved somatization and pain in the context of high levels of satisfaction with the provider–patient relationship.
We cannot yet view these results as clinically significant, however, because full clinical trials will be needed to say this. Because trained nurse practitioners achieved a clinically significant 4.0 point MCS improvement in this population2, we suspect that a full clinical trial using PCPs will produce a much smaller ES. The data also suggest that trained PCPs can obtain even greater MCS improvement with CM participation, a finding supported by the depression literature21.
We cannot exclude the possibility that the selected PCPs would have achieved better outcomes with this patient population without any additional training. Pre-post training patients seen by intervention PCP group would be needed to resolve this. We evaluated possible regression to the mean, but our sensitivity analysis using ANCOVA indicated that was not a major issue.
We have demonstrated moderate to large effect sizes in the direction predicted by previous research. While these encouraging results hold promise that PCPs may be effective with distressed MUS patients, these pilot data with a small number of subjects only allow us to conclude that a full clinical trial is indicated.
We gratefully acknowledge the generous financial support of the Department of Family Practice, Henry Ford Health System, Detroit, MI and the Dean’s Office of the College of Human Medicine, Michigan State University, East Lansing, MI. This material was presented at the annual meeting of the Academy of Psychosomatic Medicine, Amelia Island, FL on November 17, 2007.
Conflict of Interest None disclosed.