Syllabi - General Surgery - Prognosis Scenario

A seventy-five year old retired headmistress sees you in the clinic after a recent emergency admission with a peridiverticular abscess. This was successfully managed with five days of intravenous antibiotics, but your patient is knowledgeable and understands that the underlying bowel condition is unchanged. She asks what the risks of a second emergency admission are for someone in her position. She is clearly weighing up the possibility of undergoing elective surgery to prevent any recurrence. You tell her you will review the literature to find out the chances of repeated severe complications in patients who have had one emergency admission for a complication. You explain that the risks are of recurrent peridiverticulitis, abscess or phlegmon formation, perforation, obstruction or haemorrhage. You formulate the query: In patients admitted as an emergency with complications of diverticular disease, what is the risk of a second emergency admission for further complications?

You search Medline using the terms 'diverticulosis' and 'complications' and find a relevant article.
Br J Surg 1994;81:733-5

Read the article and decide:

• Are the results of this study of prognosis valid?
• Are the results of the study important?
• Can you apply this valid, important evidence about prognosis to the treatment of your patient?

Completed Prognosis Worksheet for Evidence-Based General Surgery

Citation

Farmakis N, Tudor RG & Keighley MRB. The 5-year history of complicated diverticular disease. Ann Surg Oncol 1998;5:265-70

Are the results of this prognosis study valid?

Was a defined representative sample of patients assembled at a common (usually early) point in the course of their disease?

Yes. All patients were studied from the time of first emergency admission for complications of diverticular disease.

Was patient follow-up sufficiently long and complete?

Only 120 of 176 (68%) cases were successfully traced, and follow-up was a minimum of 5 years, by which time 1/3 of the patients had died. The median follow-up was not recorded.

Were objective outcome criteria applied in a "blind" fashion?

Questionnaires were sent to the GPs of all patients with an index emergency admission, asking about recurrent admissions, symptoms, operations, deaths and cause of death.

If subgroups with different prognoses were identified, was there adjustment for important prognostic factors?

Subgroups were not identified.

Was there validation in an independent group (test set) of patients?

No.

Are the valid results of this prognosis study important?

How likely are the outcomes over time?

Death from diverticular disease: 1.7% per year. Further serious complications: 6.5% per year. Readmission with further complications: 2.5% per year*. Continuing symptoms at 5 years: 33%.

How precise are the prognostic estimates?

95% Confidence intervals are: for death, 0 - 3.9% per year. For further serious complications, 2.1 - 10.9% per year. For readmission 0 - 5.3% per year. For continuing symptoms at 5 years: 24.6 - 41.4%

Can you apply this valid, important evidence to the management of your patient?

Were the study patients similar to your own?

As far as we can see, yes.

Will this evidence make a clinically important impact on what you offer to or tell your patient?

Yes

Additional Notes

• The 77 patients in this cohort who had emergency colectomy had a very low risk of further complications (2/77), whereas 37 of the 43 who had conservative treatment had further severe complications.
• No data is given about the mortality of emergency colectomy in this group. In the contemporary study of Sarin and Boulos (Ann. Roy. Coll. Surg. Eng. 1994; 76: 117-20.) this was 12%. This paper quotes a similar rate of re-admission (2% per year), and agrees that those who had a colectomy are at very low risk for recurrent problems.
• The incomplete follow-up and multi-centre nature of the study suggest possible sources of selection bias.

Clinical Bottom Line

There is a significant risk of further severe complications in patients similar to mine. There is therefore a case for elective prophylactic resection, and some indirect evidence that it is likely to be effective: it is also likely to carry a significant mortality rate. An RCT is needed to determine the balance of risks and benefits in a defined patient group.

Diverticulitis - Risk of recurrent admission and death after first emergency admission

Clinical Bottom Line

Diverticulitis - Risk of recurrent admission and death after first emergency admission.

Citation

Farmakis N, Tudor RG & Keighley MRB. The 5-year history of complicated diverticular disease. Ann Surg Oncol 1998;5:265-70

Clinical Question

In patients admitted as an emergency with complications of diverticular disease, what is the risk of a second emergency admission for further complications?

Search Terms

diverticular disease, emergency admission in Medline

The Study

• The Study Patients: patients admitted for first time with emergent complications of diverticulitis
• Prognostic Factor: emergency admission
• The Outcome: death and readmission

Study Feature	Yes	No	Can't Tell
Well-defined sample at uniform (early) stage of illness?	x
Follow-up long enough?	x
Follow-up complete?		x
Blind and objective outcome criteria?	x
Adjustment for other prognostic factors?		x
Validation in an independent "test-set" of patients?	x		x

The Evidence

Prognostic Factor	Outcome	Time	Measure	Confidence Interval
emergency admission	readmission	1 year	2.5%	0 to 5.3%
emergency admission	death from diverticular disease	1 year	1.7%	0 to 3.9%

Comments

inadequate follow-up (less than 80%)