Chronic pain associated with inadequate Vitamin D levels

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RHEUMATOLOGIC DISORDERS Arthur A. Schuna, Section Advisor

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Chronic pain associated with inadequate Vitamin D levels

Key point: Patients with chronic pain who have inadequate levels of vitamin D require almost twice the pain medications as similar patients who have adequate levels of vitamin D, according to an article recently reported in Pain Medicine.

Finer points: This retrospective analysis studied 267 chronic pain patients who were admitted to the Mayo Clinic Comprehensive Pain Rehabilitation Center in Rochester, MN, from February 2006 to December 2006. At the time of admission to the 3-week, outpatient, rehabilitation program, relevant clinical and demographic data (e.g., age, cormorbid medical conditions, body mass index, month of admission, pain duration, principal pain site or diagnosis, opioid intake, and duration of opioid use) were collected. Each patient’s geographic residence above or below latitude 37°N was also determined, because residence above 37°N is generally insufficient to produce adequate vitamin D levels during winter months. In addition, opioid usage at admission was determined from medical records and from patient’s self-reported usage. For analysis purposes, researchers converted opioid intake to oral morphine equivalents. Last, all patients completed the Short Form-36 Health Status Questionnaire (SF-36) to assess health status and general well-being.

Serum 25-hydroxyvitamin D levels were obtained at admission for all patients. Patients with levels of 20 ng/mL or less were considered to have inadequate levels of vitamin D; patients with levels greater than 20 ng/mL were considered to have adequate levels of vitamin D. All patients who had inadequate levels of vitamin D were given vitamin D supplementation.

Of the 267 patients evaluated, 74% (n = 198) had adequate vitamin D levels and 26% (n = 69) had inadequate vitamin D levels. The mean (± SD) serum 25-hydroxyvitamin D level for the entire cohort, vitamin D inadequate group, and the vitamin D adequate group was 28.7 ± 11.6, 15.7 ± 4.0, and 33.3 ± 9.8 ng/mL, respectively. A comparison between the two groups found no significant differences in age, sex, pain duration, pain diagnosis, residence above or below latitude 37°N, or frequency of comorbid medical conditions.

The proportion of patients who used opioids and who had inadequate vitamin D levels was 55% (38 of 69) compared with 52% (102 of 198) for patients who had adequate levels of vitamin D. Among the patients who used opioids, the mean oral morphine-equivalent dose for patients who had inadequate vitamin D levels was 133.5 mg/day compared with 70.0 mg/day for patients who had adequate vitamin D levels (P = 0.001). The mean duration of opioid use for patients who had inadequate vitamin D levels was 71.1 months compared with 43.8 months for patients who had adequate vitamin D levels (P = 0.023).

The SF-36 assessment found that patients with inadequate vitamin D levels who used opioids had worse physical functioning (P = 0.041) and health perception (P = 0.003) than patients who also used opioids but who had adequate levels of vitamin D.

What you need to know: Low 25-hydroxyvitamin D levels are common in adults. This study suggests a relationship between low vitamin D levels and pain perception, resulting in the need for higher narcotic doses. Based on the findings of this study, recommending vitamin D supplementation to better manage chronic pain might seem prudent. However, results of double-blind studies have been disappointing.

Chronic diffuse pain can be a symptom of osteomalacia, and vitamin D supplementation may be beneficial in this setting. Low vitamin D levels increase the likelihood of osteoporosis, and supplementation should be considered in patients with low levels.

What your patients need to know: Explain to patients that there are three primary sources of vitamin D—sunlight, diet, and supplements. Generally speaking, 10 to 15 minutes of sun exposure (three times per week) is enough to maintain adequate vitamin D levels. Patients should also be encouraged to consume recommended daily allowances through foods that contain vitamin D (e.g., dairy products, fish, oysters, fortified cereals, margarine). Vitamin D supplements should only be considered for patients who do not get necessary vitamin D through sunlight and diet.

Sources

 

Turner MK, Hooten WM, Schmidt JE, et al. Prevalence and clinical correlates of vitamin D inadequacy among patients with chronic pain. Pain Med. 2008;9:979–84. Straube S, Moore RA, et al. Vitamin D and chronic pain. Pain. 2009;141:10–3.

Related resources on www.pharmacist.com

 

ADIL, August 2008. Vitamin D deficiency adversely affects cardiovascular health. ADIL, September 2008. Clinically relevant vitamin D and atorvastatin interaction.

Joe Sheffer (jsheffer)Posted April 7, 2009