I’ve read with interest a number of recent publications that suggest that cognitive behavioural therapy (CBT) may be less effective in patients receiving disability benefits versus other patients. The theory here is that the specific circumstances of being on disability benefits may somehow lead to poorer outcomes following CBT.

There’s some evidence in other clinical areas (a meta-analysis of surgical outcomes by Harris et al) that shows how compensation status can act as a potential confounder. This sizeable review found a substantially greater risk of poor outcomes (functional, quality of life, pain and patient satisfaction) after surgery in patients receiving benefits (odds ratio [95% CI] = 3.79 [3.28 to 4.37]).

So, is there a difference in the effect of CBT on depression between those receiving disability benefits compared with those who don’t? Well, a new systematic review and meta-analysis published in PLOS ONE seeks to answer this very question.

Methods

The authors hail from far and wide (the Netherlands, Canada, Colombia, Egypt and Chile) and they have done a commendable job given that this is a tough review to carry out. First of all they had to conduct a literature search to find randomised controlled trials (RCTs) of depressed patients that compared CBT with a control (minimal/no treatment, treatment as usual, drug treatment or CBT and drugs). Studies were selected independently by 3 teams of reviewers and they performed an individual patient data meta-analysis to summarise the data.

They found 92 RCTs to include and managed to contact the authors of 80% of these studies to ask if they captured receipt of benefits as a baseline characteristic. Eight of the trials did and 3 actually enrolled patients in receipt of benefits, 2 of which provided the necessary individual patient data to be included in their primary analysis (involving 227 patients in total, 34 in receipt of disability benefits and 193 not).

Results

• Patients on disability benefits had a greater severity of depression than those who were not receiving disability benefits (baseline BDI-II of 32.9 versus 26.9)
• The review found no significant difference in the effect of CBT between patients on disability benefits and those not receiving benefits
• All results of the 2 pooled trials suggested a possible benefit of CBT on depression:
  • Both those receiving and not receiving disability benefits (MD = -2.61; 95% CI = -5.28 to 0.07; p = 0.06, minimally important difference [MID] = 5)
  • Just patients on disability benefits (MD = -6.88; 95% CI = -14.06 to 0.31)
  • Just patients not on disability benefits (MD = -2.22; 95% CI = -5.07 to 0.63)

Conclusions

The reviewers concluded:

If the use of CBT to manage depression among patients receiving disability benefits was less effective than in patients not receiving disability benefits, clinicians and payers might reasonably choose alternative treatment strategies (e.g. pharmacotherapy, other psychotherapies or a combination of both).

The limited evidence available, however, provides no support for this hypothesis and suggests that, for the time being, CBT should continue as a recommended approach for addressing depression in patients receiving disability benefits.

Secure inference will, however, only be possible after the conduct of much larger comparative trials, conducted with low risk of bias and in collaboration with insurers.

Clearly this is a review that must be interpreted with caution as there were only 34 patients receiving benefits included in the primary analysis. Hardly a big sample!

The secondary analysis of patients not receiving benefits showed substantial heterogeneity, which was possibly caused by variations in the severity and duration of the depression and the quality and frequency of the CBT given.

Certainly a subject to keep an eye on, that requires more high quality randomised studies before we can come to a more definitive conclusion.  Where have you heard that before eh?

Link

Ebrahim S, Montoya L, Truong W, Hsu S, Kamal el Din M, et al. (2012) Effectiveness of Cognitive Behavioral Therapy for Depression in Patients Receiving Disability Benefits: A Systematic Review and Individual Patient Data Meta-Analysis. PLoS ONE 7(11): e50202. doi:10.1371/journal.pone.0050202

Harris I, Mulford J, Solomon M, van Gelder JM, Young J (2005) Association between compensation status and outcome after surgery: a meta-analysis. JAMA 293: 1644–1652. doi: 10.1001/jama.293.13.1644.