Predicting Survival Time in ALS

by Margaret Wahl and Amy Labbe on Fri, 2009-05-01 15:33

God grant me the serenity to accept the things I cannot change; courage to change the things I can; and wisdom to know the difference. — from a prayer by Reinhold Niebuhr

There are few things that are certain in ALS, including what to do to ensure (or avoid) longer survival time. There are several factors influencing longevity with this disease over which one has no control, but there are a few things one can do to survive longer.

Changing the things one can

There are generally three things you can do to prolong survival that have the support of experts in the field: maintain nutritional status, including getting a gastrostomy tube (which goes straight into the stomach, not down the throat) when and if necessary; use assisted ventilation as respiratory status deteriorates; and take riluzole unless side effects or other medical conditions preclude doing so. People with ALS generally agree on these interventions as well, often finding them less onerous than they had anticipated.

Get enough to eat and drink

Most people find a gastrostomy tube is much more comfortable and easy to use than they thought it would be.

Malnutrition, present in 16 percent to 50 percent of people with ALS, is a predictor for worsened survival, according to a study published in 2000. The main cause of malnutrition in ALS is swallowing dysfunction, resulting from paralysis of muscles involved in swallowing, but weakness of the muscles involved in chewing food also contributes, as does a higher than normal metabolic rate of uncertain origin in this disease.

A vicious cycle can ensue, in which poor nutrition exacerbates weakness, and weakness in turn limits food and liquid intake.

Signs of insufficient intake of calories may be obvious, such as excessive and rapid weight loss. But for those who like an objective measurement, a body mass index (BMI) of less than 18.5 is considered a red flag. To calculate your BMI at National Heart Lung and Blood Institue.

While you can still swallow and chew safely, take in foods and liquids that are dense in calories, such as high-calorie shakes and bars, and high-protein foods like meat, fish and eggs. Drink plenty of fluids to avoid dehydration.

When eating and drinking are no longer safe because of fear of choking, or when eating a meal takes so long you become exhausted, it’s time to consider a gastrostomy, or PEG, tube. PEG stands for percutaneous endoscopic gastrostomy tube, which relates to how the tube is inserted. The end result of PEG tube insertion is a small tube that goes directly into the stomach from outside, not something that goes through the nose or down the throat.

Most people find it’s much more comfortable and easy to use than they thought it would be.

A very active online forum is ALS Forum operated by the ALS Therapy Development Institute (an ALS research institute in Cambridge, Mass., supported by MDA) and provides a variety of opinions and experiences with the PEG tube and other aspects of ALS therapy.

From a recent post: “Best thing I could have done! No more choking, no more dehydration, no more weight loss. ... When I got mine I was still walking and drinking normally but having trouble with food, and I’d lost 35 kilograms (77 pounds). It would be fair to say I was in denial, and it took a while for me to adjust to the idea of having limited food intake. Now I can’t believe I was so silly.”

Breathe well

Noninvasive ventilation can prolong life despite a decline in respiratory muscle function.

As the muscles involved in respiration — the diaphragm and the intercostals, which are between the ribs — weaken, it becomes harder and harder to move enough air in and out of the lungs. This is especially true when lying on one’s back, as the weight of the abdominal organs creates even more resistance for the weakened diaphragm.

In recent years, a large percentage of ALS patients have opted for “noninvasive ventilation,” or NIV, to help them with their breathing. NIV delivers air under pressure (with a normal percentage of oxygen, not an oxygen supplement) to the lungs via a face mask or mouthpiece.

A 2007 study showed starting NIV earlier prolongs survival better than starting it later, when respiratory function is worse. This study used 65 percent of normal forced vital capacity (the amount of air one can exhale after taking in a deep breath) as the dividing line between early and late intervention. People who started using NIV when their forced vital capacity was at least 65 percent survived an average of 329 days longer than those who started it when their FVC was lower than 65 percent. NIV can be used for as many hours of the day or night as the person wishes and can easily be taken on and off.

Although NIV may prolong life by months or even sometimes years, for indefinite survival with ALS, “invasive ventilation,” which means ventilation through a tracheostomy tube, is almost always required. A tracheostomy is a surgically created opening in the trachea. Not only the delivery route but the type of ventilation device used with it provides for more complete substitution for normal respiratory muscle function than does NIV.

Surprisingly few studies have followed the course of people with ALS who have opted for invasive ventilation. In fact, many studies use “death or tracheostomy” as an end point, implying that these are approximately equal. That, however, is certainly not the case, so it may be that following people with tracheostomy ventilation until death would take so long the study could not be wrapped up in a timely fashion.

A small study published in 2003 in the journal Neurology found that, out of 70 people with ALS in Tokyo who opted for tracheostomy ventilation, 33 survived more than five years on it. In that group were three people who lived for 10 years on tracheostomy ventilation and two who survived for 18 years. The most common cause of death was pneumonia, followed by cardiovascular disease.

The down sides of tracheostomy ventilation are that it requires respiratory care that poses a significant burden on family members or costs a great deal if professionals are hired to help, and that it may allow for prolonged survival even when all voluntary muscle movement has been entirely lost and even communication is difficult. Still, many people are happy with this option.

“My wife decided to follow the doctor’s suggestion and get her trach early,” noted an ALS TDI Forum visitor in March. “It’s been over two months now, and it has made a huge difference. She looks 10 years younger, has good color, and hasn’t taken a nap since the procedure. She was on BiPAP about 17 hours a day before the procedure. Her oxygen saturation has been excellent. ... Caring for her can be a bit overwhelming at times, but it sure is a lot better than the alternative. We are convinced we made the right decision!”

Consider riluzole

In the 1990s, a drug called riluzole (brand name Rilutek) was extensively tested in ALS and found reasonably safe and modestly beneficial. It was ultimately approved by the U.S. Food and Drug Administration (FDA) for use in treating ALS. So far, it’s the only drug to obtain FDA approval for this specific indication.

Riluzole is believed to interfere with the action of glutamate, a chemical transmitter of signals in the central nervous system that, if present in excess or for too long a time in the vicinity of nerve cells, can cause damage. This is generally considered to be the mechanism through which riluzole exerts its modest benefits in ALS.

A study published in 1996 of 959 people with ALS treated with either riluzole or a placebo (inactive substance) found that, after 18 months, 134 out of 236, or 56.8 percent, of those taking 100 milligrams a day of riluzole were alive and without a tracheostomy. In the placebo group, 122 out of 242, or 50.4 percent, had survived and didn’t have a tracheostomy. (There were two other dosage levels of riluzole, all of which showed some benefit for the drug.)

Riluzole was found capable of causing liver problems, so liver function has to be monitored, and serious abnormalities on tests of liver function may require discontinuation of the drug. In addition, some people in the study developed increased weakness, nausea, vomiting, dizziness and/or sleepiness that resolved with a reduction in their riluzole dosage.

Later studies led to the conclusion, which is often quoted, that riluzole prolongs survival with ALS by about two or three months. Unfortunately, many people have interpreted this to mean the two or three months would be spent in the final stages of the disease, with little function or life quality remaining.

This, however, is not borne out by research. In 1998, investigators reanalyzed the data from the 959-person riluzole study, dividing participantsinto mild, moderate, severe and terminal “health states” at various time points. (They were able to do this for all but five trial participants.)

They found the riluzole takers spent significantly more time in the “moderate” health state than did people taking a placebo but not in the mild, severe or terminal states of the disease. That study suggests thatmost people whose lives are extended by riluzole spend the extra time in an earlier, rather than later, stage of the disease.

A down side of riluzole is its high cost, estimated at about $600 to $900 a month. Some insurance plans offer full or partial coverage. Medicare prescription drug plans offer partial coverage.

From the Forum: “Each person has to make their own decision. ... I find it hard to believe my mom could have deteriorated faster without Rilutek, but maybe that might have happened.”

“How would you know if it was helping or not? I can guarantee if you don’t take it, it won’t help.”

Accepting the things that can’t be changed

The progression of ALS and length of survival after disease onset are both highly variable from one person to another.

That said, a number of studies have revealed some “unalterable” (outside the control of the individual) factors that appear to predict the course of ALS. (See “Factors in Survival.”)

One always should keep in mind that ALS ultimately is unpredictable. It’s generally not possible to know with a high degree of accuracy, using these or other factors, how one’s own disease might progress.

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