New Update: Vitamin D has No Effect on Knee Osteoarthritis

Vitamin D supplementation for individuals with knee osteoarthritis and low 25-hydroxyvitamin D levels did not reduce knee pain or slow cartilage loss, according to a study appearing in the March 8 issue of JAMA.
 
Symptomatic knee osteoarthritis occurs among 10 percent of men and 13 percent of women age 60 years or older. Currently, there are no disease-modifying therapies for osteoarthritis. Vitamin D can reduce bone turnover and cartilage degradation, thus potentially preventing the development and progression of knee osteoarthritis. Observational studies suggest vitamin D supplementation is associated with benefits for knee osteoarthritis, but current evidence from clinical trials is contradictory.
 
Changhai Ding, MD, PhD, of the University of Tasmania, Hobart, Tasmania, Australia, and colleagues randomly assigned 413 patients with symptomatic knee osteoarthritis and low 25-hydroxyvitamin D to receive monthly treatment with oral vitamin D3 (50,000 IU; n = 209) or an identical placebo (n = 204) for 2 years. The study was conducted in Tasmania and Melbourne, Australia.
 
Of 413 enrolled participants (average age, 63 years; 50 percent women), 340 (82 percent) completed the study. The researchers found that vitamin D supplementation, compared with placebo, did not result in significant differences in change in MRI-measured tibial cartilage volume or a measure of knee pain over 2 years. There were also no significant differences in change of tibiofemoral cartilage defects or change in tibiofemoral bone marrow lesions. Vitamin D levels did increase more in the vitamin D group than in the placebo group over 2 years.
 
“These data suggest a lack of evidence to support vitamin D supplementation for slowing disease progression or structural change in knee osteoarthritis,” the authors write. 

Patients Believe Lab Tests More Than Doctors

A colleague recently made this declaration among a group of rheumatologists. There was a long group pause that made me consider this observation. This is an important issue, because it is sad if true and we may be leaving our patients with the wrong impression. It’s also important as new laws have liberalized the patients’ rights to his/her lab tests and records.

Thus, why do patients believe their labs more so than their doctors? And what do physicians do with this open sharing of lab values? To understand this we should look at both the patient and physician perspective on this issue.

The Patient Perspective

• Trust a doctor or trust a lab number? Doctors are human, occasionally fallible or poorly groomed. Not surprisingly, it takes a while for patients to learn to trust a physician. Urgency and severity don’t engender trust either. My new patient with the melon-sized, swollen, hot knee may trust the prescription given but will trust less when I’m wielding a large needle and 20 cc syringe. Physicians’ lingo also undermines trust. I think patients are perplexed when we deliver the shortest possible message using the longest possible polysyllabic terminology. Medical speak is the third leading cause of patient bewilderment and malpractice suits. Patients are keenly aware that if a doctor cannot speak plainly, there must be something wrong with the doctor, rather than the patient.
• Laboratory tests on the other hand, are numbers - and numbers don’t lie (the latter is likely to be attributed to an accountant or administrator, not Osler). Numbers are countable, incremental and delivered by and/or on computer printouts. Hence, those values that appear in red and are “out of range” are meaningful to the owner or those red values. Even though I try to convince my patients that the red, seemingly elevated BUN/Creatinine ratio is not important, my patients are not easily convinced. I use the analogy that driving at 37 MPH (in a 35 MPH zone) may be considered speeding; no one gets a policeman’s ticket for such a number. Or that the number has to be interpreted in context. So if I’m driving 37 MPH in a school zone full of flashing buses and crossing guards, a penal code prize will be duly served.
• Everyone values free stuff. You don’t always get your money's worth in healthcare and when you don’t, it costs more. These are the built in pitfalls of healthcare and physicians that every patient must cope with. Cognitive dissonance may explain why humans value that which is free, but still I’m amazed when patients are compelled to react (without calling me) to a TV news report or a pharmacy six-page printout or a lab report. These info bits, presumably from authoritative sources, are valued and believable as they are free, personalized and clear in their message. This contrasts with physician messages that are expensive, occasionally uninterpretable and delivered at the end of a rushed medical visit.
• Doctors specialize in messaging that isn’t so clear.  We commonly use statements like, “you’re much better or “this is a setback”. Patients wonder whether “better” is relative to my last visit or other patients on the better to worse scale. This contrasts with lab tests are quantitative and digital. Patients believe that a lab test is a numeric systematic representation their biology and a pivotal arbiter of wellness. This they can understand – or at least look up on Google. My labs say I’m either normal like everyone else or a red number, falling out of range. “Doc my lab must mean I’m at least as abnormal as the test says I am”.
• Doctors are to blame. Patients think labs are important because doctors tell them so. “Let’s wait and see what the labs show” (meaning I can’t make a diagnosis without them). “Your labs are just fine” (implying the patient must be also). “Mr. Sample there’s a problem with your labs” (uh-oh, sell the farm Mr. Sample!). Then Dr. Jekyll becomes Dr. Hyde when the patient wishes to discuss lab abnormalities only to observe the doctor dismiss the labs as either hanging chads in a meaningless election or a result that should never have been reported (because it takes too long to explain why the result in physiologically unimportant even though it may be psychologically damaging). I’m not surprised when my patients struggle and say it’s sometimes hard to tell who I should believe, the lab test or the doctor.

The Physician Perspective

Laboratory testing is usually an integral part of comprehensive healthcare delivery. Testing can be used to assess a patients metabolic status, organ function, immunologic abnormalities, disease risk, drug safety or toxicity, and occasionally a diagnosis.

Labs are important. But a lab is meaningless without a symptom narrative, list of diagnoses or drugs, or a detailed patient examination. Clinicians need labs to answer specific questions and use them as adjunctive “info bits” to enhance their understanding of the disease, management of the patient and safety of therapies given.

Patients want and should have their lab results. But it is the physician’s responsibility to educate their patients about labs, why they are being done, what is being examined and looked for. Here are a few principles of lab testing that clinicians need clearly communicate to their patients and payers of labs:

• A lab test does not equal a diagnosis. Hence, while we would like to see a positive rheumatoid factor in someone with suspected of rheumatoid arthritis, this test is not required to establish the diagnosis.
• More labs means more chances for an abnormal finding. The more lab tests that are ordered, the more likely one or more will fall out of normal range. Normal values of a particular lab reflect the bell curve limits established in a large number of “normal” people. Values that fall “out of range” beg the question, “when is abnormal really abnormal?” Explaining the difference between a random spurious finding and a pathologic result can be difficult, but requires trust and communication between patient and physician.
• Monitoring and serial labs. Labs are important when monitoring disease status (e.g., sed rate or creatinine) or drug toxicity. This is why repeated or serial labs may be necessary.
• Once is enough!  Many autoimmune laboratory tests need only be done once or confirmed by a second by different lab. Hence there is no value in repeating and following the following tests: ANA, RF, CCP, ENA or ANCA as these have not been shown to change as the disease does. There are other tests often used as a “disease activity” measure – these can be quite valuable in certain clinical situations.
• Result communication.  Physicians and patients need to have an agreed upon plan addressing how the patient will learn about his/her lab results.
• Patient folders.  Patients need to keep copies of their labs in a folder, bring these to all medical visits and share the results with all caregivers.

Patients should understand their labs and believe that they are being used to effectively diagnose and treat their medical predicament. They should be given copies and encouraged to maintain a file of their wellness and labs to share with other doctors. Patients who are overly fixated on a specific lab result are that way because we made them that way! It’s the physicians’ responsibility to educate the patient on which labs are needed or important and when concern over a lab results is appropriate.