Optimizing D-penicillamine Treatment for Rheumatoid Arthritis?

Summarized by Robert W. Griffith, MD
April 4, 2007

Summary

Disease-management education improves rheumatoid arthritis patients' compliance with D-penicillamine medication. Improved compliance, however, doesn't affect the clinical course of the disease.

Introduction

As part of our review of patient adherence to medication we have covered the importance of taking prescribed medications for cardiovascular disease, high blood pressure, cancer, and osteoporosis. Somewhat surprisingly, rheumatoid arthritis, where symptoms such as pain play a prominent role, is also a candidate for enhanced patient education. Improving patients' compliance with their physicians' prescription orders is likely to improve their symptoms and slow their disease progression.
This approach was the subject of a study conducted in the UK and reported in the Annals of Rheumatic Diseases; here is a summary of this study's findings.

What was done

One hundred consecutive patients at Leeds Royal Infirmary, UK, who were deemed to require D-penicillamine (DPA), were randomly assigned to enter a patient education program or to receive 'usual care'. There were 51 patients in the education program and 49 'usual care' controls.

Visits for all patients were scheduled monthly, for six months. The 30-minute monthly education program, which was conducted by the same rheumatology nurse practitioner, consisted of information on the types of drugs for rheumatoid arthritis, the disease process itself, physical exercise, joint protection, pain control, and coping strategies. Patients received an information leaflet as back-up; the same leaflet was provided to the control group. The control subjects were invited to talk about their social lives and families at their 30-minute visits.

Patients were advised that their DPA would contain a small dose of phenobarbitone to assess the effectiveness of the drug. Blood was taken at monthly visits for phenobarbitone level, plasma viscosity, and C-reactive protein (CRP), and assessments of articular index, morning stiffness, and pain scores were done at the same time. Those participants with phenobarbitone levels indicating less than 85% of the prescribed DPA dose had been taken were declared poorly adherent.

What was found

Most of the patients in the study were female. Their ages ranged from 22 to 79, and they had had rheumatoid arthritis for an average of 12 years.

Of the 100 patients who entered the study, 63 completed the full 24 weeks - 33 in the education group and 30 controls. The drop-outs were due to potentially hazardous side effects - DPA is a potent drug with occasional severe side effects.

Over 450 blood samples were collected and assayed for phenobarbitone. The result showed that those patients in the educational program were significantly more likely to be taking their DPA medication on more occasions than those in the 'usual care' group. There was 14% non-adherence in the education group, compared with 19% in the control group, with the controls being adherent on fewer occasions than their counterparts.

When examined at intervals during the study it was clear that there was no difference in adherence to medication between the two groups in the first 8 weeks, but a trend toward greater adherence in the education group developed and strengthened thereafter. By the end of the study 85% of the education group patients compared with 55% of the control group patients were taking their DPA as prescribed.

The assessments of therapeutic outcome failed to show any differences between the two groups - in other words, the improved adherence with patient education failed to translate into better clinical outcomes in this 24-week study.

What the study shows

Patients with active rheumatoid arthritis who were candidates for D-penicillamine therapy were more likely to take their medication regularly if they participated in a patient education program. After 24 weeks, 85% of them were taking their DPA as prescribed, compared with 55% of a 'usual care' group that had no special patient education.

One would expect that improved compliance in taking an effective medication would be associated with greater clinical improvement. This was not the case here, however. Both groups in the study benefited from taking DPA, both biochemically and clinically. The authors of the study suggest this may be due to the nature of D-penicillamine; an earlier study has indicated that intermittent treatment can produce similar results to continuous treatment.¹

The important finding in this study is that patient education can improve drug adherence. This has implications for almost all chronic drug treatments where the temptation for the patient to drop therapy is often considerable. Self-management courses for arthritis patients have been shown to be very effective when administered in a group setting.² And, of course, they are applicable with even greater effect in other conditions - see the first link below.

Source

• Effect of patient education on adherence to drug treatment for rheumatoid arthritis: a randomized controlled trial. J. Hill, H. Bird, S. Johnson , Ann Rheum Dis , 2001, vol. 60, pp. 865--875

Footnotes
1. The long-term use of D-penicillamine for treating rheumatoid arthritis: is continuous therapy necessary? DV. Doyle, D. Perrett , OJF. Foster,  et al., Br J Rheumatol , 1993, vol. 32, pp. 614--617
2. A disease-specific self-help program compared with a generalized chronic disease self-help program for arthritis patients. K. Lorig, PL. Ritter, K. Plant, Arthritis Rheum , 2005, vol. 53, pp. 950--957

Related Links
Manage Your Own High Blood Pressure and Diabetes
Family Practice Notebook: D-penicillamine
Stanford Self-Management Programs: Arthritis

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