May 23, 2012

The Truth About Tube-Feeding

For the last 15 years, physicians have raised questions about the efficacy of artificial nutrition—tube-feeding—in individuals with advanced dementia. Study after study of the outcomes of feeding tubes in patients with advanced dementia has failed to show any measurable benefit. But despite the
mounting evidence, feeding tubes continue to be used. For the first time, a study has been published concluding that not only do feeding tubes fail to benefit people with advanced dementia, they actually harm them. In fact, they seem to cause one of the conditions they are intended to prevent, pressure ulcers. But is it true?

Advanced dementia is a progressive neurological condition in which there is gradual loss of all the most basic capacities, including the ability to speak, to use the bathroom independently, to walk, and to eat. Fully 86% of nursing home residents who develop advanced dementia also develop difficulty eating. Once the technology for artificial feeding became simple and widespread—a feeding tube is inserted into the stomach through a minor surgical procedure and allows liquid nutritional supplements to enter the body directly, bypassing the need for the person to chew or swallow food—the temptation to use it in anyone who couldn’t eat was irresistible, regardless of whether the cause of the problem eating was a temporary, post-surgical condition, a congenital abnormal of the gastrointestinal system or, as with dementia, an end-of-life condition. In particular, tube feeding was used in patients with advanced dementia even though it does not prevent aspiration pneumonia, a common cause of death in demented individuals in which food goes into the lungs instead of the stomach; it does not prevent pressure ulcers, another common condition in which skin breaks down due to immobility; and it does not prolong life. Tube feeding nonetheless continues to be used because families find nutrition of symbolic importance as a means of demonstrating caring,  because many physicians and families are skeptical of the clinical data, none of which are based on randomized, controlled studies, and in part because it is financially advantageous for nursing homes to tube feed demented residents than to hand feed them.

The trouble is that without a randomized trial, in which roughly half the patients are arbitrarily chosen to receive a feeding tube and the other half do not, it’s very difficult to be sure that whatever outcome is measured—whether it is pressure ulcer development or survival or anything else—is directly
related to the feeding tube. And physicians and families have been extremely reluctant to randomize patients with advanced dementia in this way to definitively answer the question. After all, the patients are profoundly cognitively impaired and unable to make decisions about whether to accept tube feeding. Their caregivers, who must make decisions on their behalf, tend to have strong feelings about tube feeding, as do their physicians. The current study attempts to circumvent the problem of bias due to non-randomization through several ingenious strategies: the patients with feeding tubes are “propensity-matched” to patients who did not get feeding tubes (the two groups are similar in terms of the major characteristics associated with the development of pressure ulcers); and patients must have recently developed advanced dementia to be enrolled in the study (the two groups are therefore similar in the stage of their disease based on standardized, federally mandated assessments performed every few months in all nursing homes).

Using a large database of just over 18,000 nursing home residents with advanced dementia, the authors of the new study were able to identify 1124 patients in whom a feeding tube was inserted and who had no pressure ulcers initially and match them with 2082 other nursing home residents who did not
receive a feeding tube and who also had no pressure ulcers. The two groups were comparable in their other medical conditions and in their risk factors for developing skin breakdown. Their six-month mortality rate was likewise similar, though it was slightly higher in the residents without feeding tubes (24.0%) than in those with feeding tubes (20.6%). The striking finding was that the risk of developing a new pressure ulcer (stage 2 or higher: ulcers are graded from stage 1, which is minimal skin erosion, to stage 4, in which the ulcer extends deep into the muscle or bone) was a shocking 35.6% in residents with gastrostomy tubes and only 19.8% in those without.

The new study also looked at whether feeding tubes could help heal existing pressure ulcers. Using an identical procedure, the authors identified 461 nursing home residents who had a pressure ulcer (stage 2 or higher) at the time the feeding tube was inserted and compared them to another similar group of 461 residents with a pressure ulcer but no feeding tube. Surprisingly, pressure ulcers improved in 34.6% of the residents without a gastrostomy tube, but in only 27.1% of those with the tube.

Prior studies have demonstrated that feeding tubes don’t help. But could it be true that feeding tubes actually make nursing home residents with advanced dementia worse off? The study’s authors try to explain their counterintuitive findings by suggesting that individuals with dementia who get a feeding tube may be physically restrained to prevent them from pulling out the tube and that the restraints impair mobility, predisposing to pressure ulcers. But this group had very limited mobility even before they had a feeding tube. The authors argue that tube feedings (the liquid dripped into the stomach through the gastrostomy tube) can cause diarrhea, which may accelerate pressure ulcer formation, but they provide no evidence that the patients in their study actually had diarrhea.

What I think is more likely, although I cannot prove this hypothesis, is that feeding tubes are just a marker for an aggressive approach to care and that it was that aggressive approach that led to the higher rate of pressure ulcers. After all, the patients in the Archives study were not randomized to receive a
gastrostomy tube. They got a tube because their families and their physicians believed that medical interventions were appropriate care for patients with advanced dementia. These medical interventions no doubt included a variety of strategies, of which feeding tubes were only one example. The current
study says nothing about what other interventions, aside from the feeding tube, the nursing home residents received after enrollment. But in a landmark study of the natural history of advanced dementia carried out by some of the same authors,fully 41% of nursing home residents with advanced dementia underwent at least one burdensome intervention in the last months of life: either a hospitalization, a visit to the emergency room, intravenous therapy, or a feeding tube. Undoubtedly, patients who were treated with one of those modalities were often treated with several of them. It seems plausible that it was the various aggressive medical treatments given to the nursing home residents with advanced dementia that caused them to develop new or non-healing pressure ulcers, not necessarily the tube feeding in isolation. It is even possible that tube feeding alone could have been beneficial, but it was typically administered in concert with a variety of other measures that produced harm.

So what can we conclude about tube feeding in advanced dementia? Without a randomized trial, we still do not know for sure what clinical outcomes, if any, tube feeding alters. Perhaps the time has come to focus on the indisputable fact that advanced dementia is a terminal condition and that only those measures that are inextricably associated with preserving the patient’s dignity and comfort, such as keeping the person warm and clean and clothed, are appropriate.

No comments: