SANTA ANA PUEBLO, N.M. — Elderly people with depression and arthritis experienced significant pain relief with duloxetine in a placebo-controlled trial reported at the annual meeting of the Academy of Psychosomatic Medicine.
Conducted by investigators from Eli Lilly & Co., the research findings also documented significant improvement in cognitive functions, primarily verbal learning and memory, for depressed patients treated with duloxetine (Cymbalta) in the 8-week, multicenter study.
“I think (these findings are) very encouraging,” investigator Dr. Michael J. Robinson, a clinical research physician at Lilly's medical division in Indianapolis, said in an interview. “Duloxetine may be advantageous for those specific cognitive symptoms.”
The results suggest duloxetine can alleviate arthritis pain, a common comorbidity in depressed elderly patients. An inhibitor of serotonin and norepinephrine reuptake, duloxetine is known to have analgesic properties and is approved for treatment of peripheral neuropathic pain in patients with diabetes.
Cognition was a primary outcome in the trial, which randomized 207 depressed elderly patients to 60 mg daily of duloxetine and 104 to placebo. The two cohorts were similar, with an average age of 73 years, slightly more women than men, and more than three-fourths the population being white. All patients were at least 65 years old and had previous episodes of depression.
Similar proportions of patients withdrew because of adverse events. The most common in the duloxetine group were dry mouth, nausea, and constipation.
Duloxetine produced faster and more significant reductions than placebo on the Geriatric Depression Scale (GDS) and the Hamilton Rating Scale for Depression (HAMD 17). On average, the GDS fell 4.07 in patients on duloxetine vs. 1.34 in the placebo cohort. HAMD 17 scores declined 6.49 with duloxetine and 3.72 with placebo.
The duloxetine cohort demonstrated significantly greater improvement in a composite score based on four cognitive tests: a mean change of +1.95 vs. +0.76 for the placebo group.
At baseline, the mean composite cognitive scores were 22.70 for the duloxetine group and 23.17 for the placebo group. Most of the improvement could be due to changes in scores on verbal learning and recall tests.
Visual analog scale scores for all 311 patients in the trial demonstrated greater improvement in back pain and “time in pain while awake” for the duloxetine cohort. In a subgroup analysis limited to patients with comorbid arthritis, 117 patients on duloxetine had significantly greater improvement in four of six pain measures, compared with 55 placebo patient scores.
At the outset, all patients with arthritis had significantly higher baseline scores on five of six pain categories assessed with visual analog scales. Overall severity was 38.3 for patients with arthritis vs. 22.5 in patients who did not have arthritis.
Arthritis patients in the duloxetine cohort had greater improvements in overall pain, back pain, time in pain while awake, and interference with daily activities. Arthritis patients in the placebo group had more headache and shoulder pain; the difference was not significant.
The mean change in overall pain scores was −6.70 for arthritis patients on duloxetine vs. −1.89 for arthritis patients on placebo. The most dramatic effect was for back pain, which fell by a mean of more than 20% with duloxetine while increasing more than 10% with placebo.
“We don't know if this is their pain due to arthritis or their pain due to depression,” Dr. Robinson said. “This is just looking at general pain outcomes.”
Baseline scores for depression and improvements in mood were similar for arthritis patients in the two arms of the trial.
In another poster at the meeting, analysis of pooled data from seven randomized, multicenter, double-blind trials of duloxetine showed symptom improvement to be similar for white, Hispanic, and African American patients. Dr. John M. Plewes of Eli Lilly was the principal investigator.