Block 12 - part 2 Flashcards
confounding factor
distortion of the relationship between an exposure and outcome due to shared relationship with something else, can either increase associated between exposure and outcome, or decrease association between exposure and outcome
4 ways of limiting confounding
restriction, matching, stratification, multiple variable regression
restriction
limit participants of your study who have possible confounders - means will have less data so difficult with multiple confounders
matching
create comparison group that is matched on the possible confounder, make case and control group as similar as possible on the confounder and then ask about exposure status
when is matching used
for strong confounders such as age and sex
stratification
analyse exposure:outcome association in different subgroups of the confounder, recombine data and use a weighted average of the strata
limitations with stratification
to take into account all confounders would require lots of strata and you may run out of data to fill all possible options in your strata
multiple variable regression
adjust for effects of multiple confounders, try and produce a linear model between outcome and different exposures - allows for adjustment of estimates for confounding
standardisation
way to limit confounding, often used to control for differences in age groups when comparing rates of disease in two populations with different age structures
standardised mortality ratio (SMR)
ratio between the observed number of deaths in a study population to the number of expected deaths
calculation for SMR
SMR = Observed (number of deaths)/expected (n.o.d)
direct standardisation
required we know the age-specific rates of mortality in all populations under study
indirect standardisation
only requires that we know the total number of deaths and age structure of the study population
when is indirect standardisation preferable
small numbers in particular age groups
why do we have waiting lists
limitless demand for health, limited resources
importance of waiting times to patients
patients condition may deteriorate while waiting, effectiveness of proposed treatment may be reduced, waiting itself can be distressing, adverse effect on family life, employment circumstances
ways to measure waiting times
average waiting time (mean.median), proportion who waited longer than x number of days, average wait of people currently on the list
theories of NHS waiting lists
backlog - implies need of occasional emergency injection of funds, demand management - waiting acts as a price to deter frivolous use, allows NHS resources to be fully employed, waiting lists are caused by underfunding and inefficiency
4 ways to reduce NHS waiting ties
manage deman, manage the queue, manage capacity, provide leadership
manage demand (reduce NHS waiting ties)
ensure each referral represents the most appropriate decision for the care of the individual patient
manage the queue (reduce NHS waiting ties)
ensure waiting lists are well managed and patients are called for treatment in appropriate order
manage capacity (reduce NHS waiting ties)
provide efficient and effective services that meet the level of demand from appropriate referrals
