DEAR DR. ROACH >> What is the best medicine for arthritis? My doctor prescribed diclofenac sodium, and another doctor said it will damage my liver and kidney with prolonged usage. As you know, arthritis is a chronic disease. Let me know what medicine I can use for arthritis.

— A.A.

Dear A.a. >> I’m assuming you mean osteoarthritis, the most common type, not an inflammatory arthritis like rheumatoid arthritis. If you don’t know which type you have, ask your doctor, since inflammatory arthritis needs very different and aggressive treatment.

The best medicine for osteoarthritis probably isn’t medicine; it’s exercise. For people who are early on in the course of arthritis, a regular exercise program improves both pain and function, but for people with more advanced arthritis, exercise may become more difficult to do. Severe hip and knee arthritis often benefit from swimming, where the load is taken off the joints and allows for less painful movement.

Diclofenac is a commonly used nonsteroidal anti-inflammatory drug that is effective for many people. All NSAIDs can cause stomach damage, including irritation, bleeding and ulcers. Heart disease remains a concern, although diclofenac in particular seems less likely than others to cause this. People with kidney disease need to be very careful about taking NSAIDs, as they can sometimes cause kidney disease. Liver disease is quite unusual with diclofenac.

Some people, such as those with knee and hand arthritis, can do very well with topical NSAIDs such as diclofenac gel. It has little (if any) risk of the gastrointestinal, heart, kidney or liver concerns. When topical therapy isn’t effective, most people choose to continue taking these medications, even after being counseled on the low but not zero risk of toxicity. They are sometimes the most effective medication treatment.

More severe arthritis should prompt a discussion about additional therapies, such as injections and surgery.

DEAR DR. ROACH >> My doctor ordered a “microalbumin creatinine ratio” test, but my result came out “unable to calculate.” Can you tell me what this means?

— J.S.B.

Dear Reader >> The test your doctors ordered is looking for protein in the urine, which is a concern because high levels can indicate one of several types of kidney disease.

The best way of determining the amount of protein in the urine — albumin is the major blood protein, which can spill into the urine — is to collect every drop for 24 hours. Although we do need to do it that way sometimes, a good substitute is the urine microalbumin to creatinine ratio. People with moderately increased albumin in the urine (or a high microalbumin to creatinine ratio) are at higher risk for developing overt proteinuria, which is a risk for chronic renal failure. They are also at increased overall risk for heart disease and death.

Experts recommend yearly testing of the microalbumin to creatinine ratio, and a high result usually prompts better blood sugar control, aggressive treatment of high cholesterol, and often medication, especially angiotensin receptor blockers or ACE inhibitors, to get blood pressure under tight control and protect the kidneys.

If your result was “unable to calculate,” that’s great news, because it means you don’t have any microalbumin. Determining the ratio involves dividing by the microalbumin result, and any mathematician knows you can’t divide by zero.

Contact Dr. Roach at ToYourGoodHealth@med.cornell.edu.