Monday, June 30, 2008

Prognostic awareness in CHF

JAMA has a really interesting article comparing heart failure patients' perceptions of their prognosis with their 'actual' prognosis. 'Actual' in quotes because they looked at their predicted survival with the Seattle Heart Failure Model and not the cohort's actual survival (although they tried to look at that as best they could.) The study involves ~120 patients (median age 61 years) from a single US cardiac center (Duke) with a broad range of heart failure severity (about half NYHA III-IV). They were asked in a couple different ways how long they thought they'd live; this was compared with predicted prognosis.

Median self-reported anticipated life-expectancy was 13 years, whereas the median predicted survival by the SHFM was 10 years, and 60% of patients thought they'd either be cured or have a normal life expectancy. Overestimation of prognosis was not associated with actual prognosis, nor with reporting that one's physician had discussed prognosis with them (which was ~2/5 of the cohort). In multivariate analysis younger age, lack of depression, and worse heart failure class were all associated with more extreme over-estimation of prognosis. (This, then, represents another study finding that depressed medically ill patients may have more accurate understanding of their illness than non-depressed patients.). The sickest, class IV, patients particularly overestimated their prognosis: as a group they gave a number similar to the overall cohort's 13 years (whereas their SHFM prognosis was ~4 years).

Looking only at those who actually died during the (median of -) 3 year follow-up from the study (about 1/3 of the patients): the authors don't give their actual self-reported prognoses, but just note their overestimation was of a similar proportion to the overall cohort's (i.e. by ~40%).

That patients with CHF overestimate their prognosis is not much of a surprise; that over half of them didn't appreciate that their disease is life-limiting is not surprising either, although more troubling (to be fair this study looked at everyone at this center, including those who might have transient/reversible cardiomyopathies, although this was likely a tiny percentage of the overall cohort). The number of patients with relatively short prognoses (~few years or less) is small in this study, which makes it tougher to know what this says about patients likely to be 'of interest' to palliative care clinicians, other than reinforcing our already-established impression of generalized prognostic ignorance. Most disturbing to me is the fact that even those patients who said their docs had talked time with them were as wrong as everyone else, making one wonder what their docs said vs. what these patients heard/chose to hear/chose to believe/etc. In my experience the biggest 'hurdle' is just helping patients appreciate that their class III-IV CHF is a life-limiting disease.

There's also an accompanying editorial, which asks the obvious question of Well, why do these patients need to know their prognosis?

However, a relevant question is "Why is it important for a given patient to be aware of precise quantitative prognostic information?" There are several treatment decisions for which this is important—if anticipated survival time in heart failure is short (<1> referral for heart transplantation or mechanical support needs to be considered. Similarly, referral for hospice or palliative care would be greatly facilitated by an accurate estimation of even shorter-term survival (approximately 6 months or less); conversely, if the expected survival time is at least 1 to 2 years, referral for implantation of a cardioverter-defibrillator would be appropriate. However, beyond these specific examples, no other therapeutic interventions for heart failure exist for which precise knowledge of the likelihood of survival matters in the decision-making process.
I've been thinking of this too, and I don't have any great answers to this. Having a sense of one's prognosis certainly becomes more important the shorter one's likely time is, and one could argue (although I have no 'data' to back this up) that knowing that it's likely to be a few years or less (like the Class IV patients) rather than 13 could make a major difference in how one spends one's time and I think should be disclosed (to most patients). But for patients with longer prognoses, what exactly is the impetus, other than if the patient wants to know him or herself? I'm curious as to readers' thoughts about this....

(See also the comments on another recent post about prognostication in CHF if you're interested.)

ResearchBlogging.orgAllen, L.A., Yager, J.E., Funk, M.J., Levy, W.C., Tulsky, J.A., Bowers, M.T., Dodson, G.C., O'Connor, C.M., Felker, G.M. (2008). Discordance Between Patient-Predicted and Model-Predicted Life Expectancy Among Ambulatory Patients With Heart Failure. JAMA: The Journal of the American Medical Association, 299(21), 2533-2542. DOI: 10.1001/jama.299.21.2533

Pallimed | Blogger Template adapted from Mash2 by Bloggermint