Sunday, April 24, 2011

The Effects of DNR Orders on Post-Surgical Outcomes

If you happened to read WebMD the other day you would have seen an article with the headlines ‘DNR Orders May Affect Surgical Outcomes’. This is a fair enough title, as the topic of the article is a recently published manuscript from the Yale School of Medicine that concludes that do-not-resuscitate (DNR) status appears to be an independent risk factor for poor surgical outcome.

At issue though is not the title though. It is the lack of a good understanding of what was actually published in the Archives of Surgery paper and the significance (or lack thereof) of the research results. As a prime example of poor reporting on this particular paper and the harm that may from it, I’m going to start off with the second paragraph in the WebMD article:
"A new study shows 23% of people with DNR orders died within 30 days after surgery compared with 8% of similarly matched surgery patients without DNR orders. They were also more likely to suffer serious complications and have longer hospital stays."

Sounds pretty convincing. I mean they were 'similarly matched', right? Well, lets take a closer look at the Archives of Surgery Article.

The authors did a retrospective analysis of 4128 individuals with a pre-existing DNR order who underwent surgery at more than 120 US hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program (ACS- NSQIP). They then found 4128 age and procedure-matched non-DNR patients as a comparison group. (An individual was deemed to have a DNR order if it was signed in the patient’s chart in the 30 days prior to surgery or if there was a DNR order but it was rescinded immediately prior to surgery).

Can you guess what you find if you match DNR to non-DNR patients only by using age and procedures?

Well the first thing you find is that matching only by age and procedure gives you a very poor match (I know – shocking). DNR patients were more likely to be admitted from somewhere other than home, had functional impairment, had a quickly worsening functional status between illness and surgery, had abnormal preoperative lab values, worse ASA class, had an inpatient procedure, had contaminated or dirty operative wounds, and had an emergent procedure. DNR patients also had more comorbidities (mean of 4.3 comorbidities vs 3.1 comorbidities for non-DNR patients).

The unadjusted outcomes reveal a very novel finding – sicker patients have worse outcomes that those who are not so sick (that’s how I would have titled my WebMD article). The sicker DNR patients (labeled as DNR patients in the study) had higher complication rates than non-sick patients (labeled as non-DNR patients). DNR patients were also more than twice as likely to die within 30 days of surgery (see table). The authors report some other unadjusted outcomes, but it’s all pretty useless given that the two groups are so very different.

The authors did attempt to adjust for multiple significant risk factors. After adjustment, a DNR order remained an independent risk factor associated with death (adjusted odds ratio). What are we to make of this? It is possible that physicians were less likely to provide life-prolonging treatments unrelated to CPR to DNR patients resulting in a higher mortality. It is also very likely some other unmeasured aspect accounted for the higher mortality, including that the DNR group may have had different goals than the non-DNR group when it came to to other life prolonging treatments.

So, what's the take home message? The study gives us evidence that individuals with DNR orders are more likely to die at 30 days than those who do not have DNR orders. However, as Ken Covinsky wrote in a previous comment on opioids and fractures, "it provides meager evidence" that DNR orders are the cause of the higher mortality.

by: Eric Widera (twitter: @ewidera)

7 comments:

Patrice Villars said...

Take home message: It doesn't matter what the study says as long as the general public is more likely to read WebMD than GeriPal (a poor decision, maybe, but that's beside the point). OPTICS, Eric. My suggestion - post on WebMD. And, thanks, again, for the good read.

NYLegalNurse said...

People forget what DNR means. Do Not resuscitate. Don't torture me if I am unlikely to come back and you are just going to break my ribs and give me a pnuemothorax!

In NYC 25% of the population has Advance Directives. Rarely do these discussions occur with health care professionals. If these people had DNR orders logically they were very ill and measures like CPR are likely futile giving them a generally poor prognosis. Sadly people don't see through the eyes of health care professionals.

Just one day I ask a laymen to walk in my shoes. Yes miracles do happen but at the expense of what quality of life.

Fern

ken covinsky said...

Once again, we see a report in the media that presents rather sensationalistic conclusions that are not supported by the research article.

The Archives article itself was good, useful, and presented balanced conclusions.

On the one hand, it would be stunning if DNR orders were not associated with higher mortality. After all, one of the major reasons patients get DNR orders is because their underlying illnesses make it unlikely CPR would be successful. By definition, they should have worse prognosis.

Still, describing what happens to surgical patients with DNR orders is very useful, and in this regard, the study makes an important contribution. Also, the finding that 25% of patients with DNR die within 30 days after surgery is an important one.

In the article, the authors emphasize the importance of carefully considering the goals of care before proceeding with surgery. For some reason, this point did not become the main point of the WebMD report. (But of course, careful discussion of the goals of surgery are important in all patients with poor prognosis--not just those with DMR orders.)

There seem to be 2 big problems with the WebMD article. First, is the lack of balance. The article goes way overboard in suggesting the higher rate of death was due to poor care in patients with DNR.

It is certainly proper to raise this issue. Even when a DNR is intended to mean nothing more than what it says (no CPR), it is possible that it sometimes leads clinicians to provide less aggressive traatment than was intended by the patient.

It would have been OK if the WebMD article noted this as one of several factors that may contribute to the mortality in DNR patients who have surgery.

Second, as is common in the media, there seems to be a misunderstanding of association and causation. As Eric notes, just because DNR is associated with higher mortality does not mean it is the cause of the higher mortality. Rather, it is almost certainly the case that the worse prognosis associated with DNR orders is the primary cause of the higher mortality.

The failure of the WebMD article to appreciate that the DNR and not DNR groups were in no way similar, and then understand the implications of this lack of similarity, is a big problem.

Brad Stuart said...

Nice commentary Eric. Here's my question. From this data, why does WebMD conclude "ADs are associated with increased post-surgical deaths" and not "currently accepted surgical indications are associated with higher death rates among sicker patients?" My opinion: blaming DNR status is less controversial than blaming too-aggressive surgical standards.

Chris Porter MD said...

DNR and patient/family decision confusion is a huge problem for surgeons. We do things to people I would never want for myself or for family. Wrote on this. http://porteronsurg.blogspot.com/2011/04/momentum.html

ajlounyinjurylaw said...

Signing a DNR means do not necessitate, don't try to save me, don't do anything to me to take me away from my destiny. No wonder the likelihood of death is at a higher percentage. That is the patients wish.

Anonymous said...

a dnr order actually means do not perform cpr if the patient is too old or sick for the process of banging on the ribs and would not benefit from it being performed. it is used to passively euthanize the old the sick and the vulnerable. if you do not have a living will stating a stay on that order you and your next of kin or chosen guardian may be declared incompetant and your welfare turned over to the public trustee and/or hospital administration whereby they may (passive euthanization is legal in canada) administer morphine drip (or tie you down) to keep you
quiet as they withold food and water until you die which takes 7-10 days normally relieving the burden on the medical system and your family.