PEPs - Clinical Quality and Evidence

Module 2 - Evidence


Teacher's Comment

Now test yourself by looking at the following examples, and answering the linked questions:

Example 1

Timing of onset of cognitive decline

A total of 5,198 men and 2,192 women were observed over a 10-year period from 1997. They were all civil servants aged between 45 and 70.

Participants’ cognitive functions were assessed three times over the study period. Individuals were tested for memory, vocabulary and aural and visual comprehension skills. The latter include recalling in writing as many words beginning with “S” (phonemic fluency) and as many animal names (semantic fluency) as possible. Differences in education level were taken into account. The results show that cognitive scores declined in all categories (memory, reasoning, phonemic and semantic fluency) except vocabulary and there was faster decline in older people. The findings also reveal that over the 10-year study period there was a 3.6% decline in mental reasoning in men aged 45-49 and a 9.6% decline in those aged 65-70. The corresponding figures for women were 3.6% and 7.4%.

Conclusion: Cognitive decline is already evident in middle age (age 45-49).

Mutliple Choice Question

What is this describing?

Example 2

Thalidomide and birth abnormalities


Congenital abnormalities are present in approximately 1-5% of babies. In recent months I have observed that the incidence of multiple severe abnormalities in babies delivered of women who were given the drug thalidomide (‘Distaval’) during pregnancy, as an anti-emetic or as a sedative, to be almost 20%.

These abnormalities are present in structures developed from mesenchyme - i.e., the bones and musculature of the gut. Bony development seems to be affected in a very striking manner, resulting in polydactyly, syndactyly, and failure of development of long bones (abnormally short femora and radii).

Have any of your readers seen similar abnormalities in babies delivered of women who have taken this drug during pregnancy?

Hurstville, New South Wales.


Mutliple Choice Question

This letter was published in the Lancet in 1961. What is it describing?

Example 3

Mind wandering and driving


Objective: To assess the association between mind wandering (thinking unrelated to the task at hand) and the risk of being responsible for a motor vehicle crash.

Design: We compared the frequency of exposures (mind wandering and confounders) between drivers responsible for the crash (cases) and drivers not responsible for the crash (controls). Cases and controls came from the same source (same period and location of recruitment). The study was conducted in the adult emergency department of Bordeaux University Hospital (France), which serves urban and rural populations of an area comprising more than 1.4 million people. Patients were recruited from April 2010 to August 2011. Trained research assistants interviewed patients using questions regarding the crash, characteristics of the patient, and distraction.

Setting: Adult emergency department of a university hospital in France, April 2010 to August 2011.

Participants: 955 drivers injured in a motor vehicle crash.

Main outcome measures: Responsibility for the crash, mind wandering, external distraction, negative affect, alcohol use, psychotropic drug use, and sleep deprivation. Potential confounders were sociodemographic and crash characteristics.

Results: Intense mind wandering (highly disrupting/distracting content) was associated with responsibility for a traffic crash (17% (78 of 453 crashes in which the driver was thought to be responsible) v 9% (43 of 502 crashes in which the driver was not thought to be responsible); adjusted odds ratio 2.12, 95% confidence interval 1.37 to 3.28).

Conclusions: Mind wandering while driving, by decoupling attention from visual and auditory perceptions, can jeopardise the ability of the driver to incorporate information from the environment, thereby threatening safety on the roads.

Mutliple Choice Question

What sort of study is this?

Open Question

Can you think of a potential source of bias in this study?

Example 4

Psychiatric disorders in prisoners

We conducted a survey of the point prevalence of psychiatric disorder in men remanded in custody in England and Wales and assessed their treatment needs.

A diagnosis of psychiatric disorder was made in 63% of those surveyed, including 5% with psychosis.

Over half of these prisoners were judged to have an immediate treatment need - most could be treated inside prison, but 9% needed transfer to a psychiatric bed outside prison.

By extrapolation, the remand population probably contains about 680 men who need transfer to hospital for psychiatric treatment, including about 380 with serious mental illness.

Prison treatment facilities for unconvicted prisoners need substantial expansion.

Mutliple Choice Question

What kind of study is this?

Example 5

Simultaneous radiochemotherapy versus radiotherapy alone in advanced head and neck cancer


Purpose: A prospective randomized multicenter trial was performed to evaluate the contribution of simultaneously administered chemotherapy (CT) and radiotherapy (RT) in previously untreated patients with unresectable stage III/IV head and neck cancer.

Patients and methods: Patients with locoregionally advanced head and neck cancer were treated either with RT alone (arm A) or simultaneous RT plus CT (RCT; arm B). RT was identical in both arms and administered in three courses with 13 fractions of 1.8 Gy each twice daily. During one course, from day 3 to 11, 23.4 Gy was delivered. In arm B, cisplatin (CDDP) 60 mg/m2, fluorouracil (5-FU) 350 mg/m2 by intravenous (i.v.) bolus, and leucovorin (LV) 50 mg/m2 by i.v. bolus were given on day 2, and 5-FU 350 mg/m2/24 hour by continuous infusion and LV 100 mg/m2/24 hours by continuous infusion were given from day 2 to 5. Treatment was repeated on days 22 and 44; a total RT dose of 70.2 Gy was administered. Treatment breaks were scheduled from days 12 to 21 and days 34 to 43.

Results: From 1989 to 1993, 298 patients were enrolled and 270 patients were assessable. Acute mucositis grade 3 or 4 was more frequent in arm B (38%) than in arm A (16%) (P < .001). Total treatment time was significantly longer in arm B than in arm A (P < .001) due to prolonged breaks. According to hematologic toxicity, scheduled drug doses were given in 74% of patients for the second course and 46% for the third course. The 3-year overall survival rate was 24% in arm A and 48% in arm B (P < .0003). The 3-year locoregional control rate was 17% in arm A and 36% in arm B (P < .004). Both arms showed similar distant failure patterns (arm A, 13 of 140; arm B, 12 of 130). Serious late side effects were not significantly different between treatment arms (arm A, 6.4%; arm B, 10%; not significant).

Conclusion: Concomitant CT offered improved disease control and survival in advanced head and neck cancer patients. Due to increased acute toxicity, more supportive care is demanded when CT is given simultaneously. Increased total treatment time does not exert a negative impact on outcome in this combined modality regimen.

Mutliple Choice Question

What kind of study is this?

Mutliple Choice Question

Which of these outcome measures is a POEM?