Test 68

Question 1

Health indicators (individuals, populations)

Answer 1

Quality-adjusted life years (QALYS) and disability-adjusted life years (DALYS) measure burden of disease for individuals or populations. Time-trade-off is commonly used for QALY calculations; years of life lost and years lived with disability are used for DALY calculations.

Question 2

Statistical tests

Answer 2

The analysis of variance test compares the mean of greater than or equal to 3 groups. The test requires a quantitative dependent variable (outcome) and a categorical independent variable (exposure, risk factor).

Question 3

Hazard ratio

Answer 3

Hazard ratios are used in survival analysis and have a similar interpretation to relative risk. A hazard ratio <1 indicates a protective effect, while a value >1 indicates a detrimental effect.

Question 4

Morbidity and mortality rates

Answer 4

The standardized mortality ratio (SMR) represents an adjusted measure of overall mortality. An SMR >1 indicates that the observed number of deaths in the population of interest (vinyl chloride workers) is greater than the expected number of deaths in the standard reference population. The statistical significance of the SMR is established by the confidence interval.

Question 5

Bias

Answer 5

The healthy worker effect is a special type of selection bias that usually occurs in occupational cohort studies when the general population is used as the reference group. The general population consists of healthy and unhealthy individuals; those who are unhealthy are less likely to be employed, whereas the employed workforce tends to have fewer sick individuals. Consequently, comparisons of mortality rates between an employed population and the general population are usually biased.

Question 6

Atrial myxoma

Answer 6

Left atrial myxomas are the most common cardiac tumors and can present with signs and symptoms of mitral valve obstruction (diastolic murmur and “tumor plop”), rapidly worsening heart failure, and new-onset atrial fibrillation. Myxomas frequently embolize systemically, leading to acute arterial occlusion in otherwise healthy patients.

Question 7

Blood transfusion

Answer 7

The major problem that leads to difficulties finding cross-matched blood in patients with a history of multiple transfusions is alloantibodies.

Question 8

Diabetes mellitus

Answer 8

In patients with diabetes mellitus treated with insulin, a reduction of the insulin dose before physical activity is recommended to prevent hypoglycemia, with the dose reduction proportionate to exercise intensity. Intake of additional carbohydrates can also reduce the risk of hypoglycemia. If the exercise is expected to be prolonged (>60 minutes) or will occur in the morning before breakfast, the dose of basal insulin should also be reduced. If blood glucose is <100 mg/dL before, during, or after exercise, additional carbohydrates (fruit juice) should be consumed.

Question 9

Melanoma

Answer 9

Patients with skin lesions suspicious for melanoma should have excisional biopsy to include the entire lesions with 1-3 mm margins of the surrounding skin and subcutaneous fat.

Question 10

Raynaud phenomenon

Answer 10

The presence of symptoms suggestive of systemic disease (arthralgias, myalgias, fever, and weight loss) in patients with Raynaud phenomenon warrants further evaluation; this may include ANA, RF, CBC, blood chemistry, urinalysis and measurement of complement levels.

Question 11

Risk, rate, prevalence and incidence

Answer 11

The standardized incidence ratio (SIR) is used to determine if the occurrence of cancer in a small population is high or low relative to an expected value derived from a larger comparison population. It is calculated by dividing the observed cases by the expected cases.