Kidney Disease & Health Archive

If you've had a stone, the problem is likely to recur — but it doesn't have to. Use these strategies for prevention.

The pain associated with kidney stones has been described by some as more excruciating than childbirth. Kidney stones are small, hard stones, formed when high levels of minerals in your urine start to crystallize in your kidneys, forming a pebble-like mass. The pain comes when these stones migrate from your kidneys through the ureters, which are the narrow tubes that carry urine from your kidneys into your bladder.

"Kidney stone pain is not subtle," says Dr. Gary Curhan, a professor of epidemiology at the Harvard T.H. Chan School of Public Health. It typically starts in the flank, at the side of the lower back. Sometimes if the stone moves, the pain migrates to the front of the body.

Kidney disease requiring dialysis or transplant is far more common among African Americans than among white Americans, but genetics and biology play only a small role in this excess risk; the difference is linked to social and economic injustice rooted in systemic racism, and all the added burdens associated with it.

On call

Q. I want to avoid another kidney stone attack. What's your advice about diet, coffee, tea, and alcohol?

A. The foods you eat and the amount of fluid you drink can contribute to some types of kidney stones. Certainly, you can help prevent recurrent kidney stones by paying attention to your fluid and food intake.

Research we're watching

A unique diabetes drug shows heart-related benefits in people with diabetes who also have recently worsening heart failure or kidney disease, according to two new studies.

The drug, sotagliflozin (Zynquista), belongs to a class of drugs called SGLT2 inhibitors, which cause the kidneys to release more sugar into the urine. The drug is also an SGLT1 inhibitor, meaning it decreases sugar absorption in the intestines. This dual action lowers high blood sugar, the hallmark of diabetes. In people with kidney disease, sotagliflozin lowered the total number of deaths from cardiovascular disease and hospitalizations and urgent visits for heart failure by about 26% compared with a placebo. In a second study, which included people with recently worsening heart failure, those taking the drug had a 33% decrease in those same heart-related measures compared with a placebo.

Ask the doctor

Q. I read that the death rate from COVID-19 is going down, but that people who recover from the infection still can remain sick for a long time. Is that true?

A. It is true, but we don't yet know how big the problem is: COVID-19 has been with us for only a year, and there hasn't been enough time to know the long-term effects.

Surprising factors influence urine color and odor including food and medication

Many things can alter the look and smell of your urine. When should you be concerned?

Nearly six and a half cups — that's how much urine the average person produces a day, usually in four to eight trips to the toilet. The ritual is so routine that most of us pay little attention to our urine — that is, unless it happens to look or smell different than usual.

Urinary bleeding can be dramatic and frightening, prompting an appropriate call to your doctor. But sometimes the call travels in the other direction; many people are surprised and alarmed to get a call from their doctors reporting that the urine that looked clear in the specimen jar actually contains red blood cells (RBCs). Either way, blood in the urine, known technically as hematuria, requires medical evaluation. Although the results are often reassuring, hematuria is a warning symptom that you should never ignore.

Blood can enter the urine from any place in the urinary tract. So the first step in understanding hematuria is to understand your anatomy.

On call

Q. When should I worry about changes in the color of my urine? What color is considered healthy?

A. If a person is well hydrated, the normal color of urine is a pale yellow. Someone who drinks large amounts of fluid or takes diuretics (water pills) can have almost clear-looking urine. A dark yellow color may indicate a need to increase your fluid intake.

A substance called trimethylamine N-oxide, which is produced when your body digests red meat, may raise the risk of cardiovascular problems.

Experts used to think that red meat raised your risk of heart disease simply because it was high in saturated fat. But today that picture has gotten more complicated thanks to the discovery of a metabolite — a substance produced during digestion and metabolism — called trimethylamine N-oxide, or TMAO.

According to a news article published June 11 in JAMA, three recent analyses have linked high blood levels of TMAO with a higher risk for both cardiovascular disease and early death from any cause. In one of those studies, researchers found that people with higher levels of TMAO in their blood may have more than twice the risk of heart attack, stroke, or other serious cardiovascular problems, compared with people who have lower levels. Other studies have found links between high TMAO levels and heart failure and chronic kidney disease.

Kidney stones strike twice as many men as women, but there are simple ways to stop their formation.

 Image: © pixologicstudio/Getty Images

If you've ever passed a kidney stone, you will never forget it, and you'll do anything to avoid it again. If you haven't, here is what you could expect: unbearable pain centered in your mid- to lower back that often comes in waves for 20 minutes to an hour at a time, until the tiny stones finally pass out of the body through your urine.

Unfortunately, as you age, the odds of getting kidney stones tends to rise. "Kidney stones are more common in men than in women, and in about half of people who have had one, kidney stones strike again within 10 to 15 years without preventive measures," says Dr. Brian Eisner, co-director of the Kidney Stone Program at Harvard-affiliated Massachusetts General Hospital.