Week 3: revisist Flashcards
(75 cards)
Pharmacoepidemiology
-study of use, risks, and benefits of drugs in populations (not individuals)
-pharma + epidemiology
-studies to estimate beneficial or adverse effects in population
experimental vs quasi/nonexperimental (observational)
-experiment: RCTs
-nonexperimental (observational): case-control, cohort
pharmacoepidemiologic and pharmacovigilance studies are primarily ___
-observational (nonexperimental)
Applications of pharmepi
-new info from premarketing studies
-better info on ADRs (more ppl w more conditions)
-patterns of use
-economic impact
-drug safety
-ethical and legal obligation
Data sources for pharmepi
-ADR reports (many go unreported tho)
-medical claims data (private, gov, insurance, some sold by companies): (diagnostic, procedure, lab, rx codes); (not very granular)
-EMRs (granular, but tmi)
-Indiana Network for Patient Care (INPC)
Indiana Network for pt care (INPC)
->100 separate healthcare entities providing data
-hospital, health networks, insurance providers
->18 million pt
-rx data
Limitations of observational studies in pharmepi
-confounding (independently related to BOTH exposure and outcome)
-information bias
-detection bias
-selection bias
-referral bias (encounter due to drug tx)
-protopathic bias (drug initiated before diagnosis)
-prevalence bias
-lag time
-immortal time bias (pt will not survive to measure outcome)
Information bias
-related to info regarding exposure/outcome
-includes measurement and/or classification error, or patient reporting/recall
-hawthorne effect: knowing they are being studied
Detection bias
-specific outcome dx preferentially in subjects exposed to agent
-more likely to look for an AE in someone exposed to a drug
-more pt on amiodarone may report more pulmonary toxicity but that is bc they are also being more routinely screened
-investigator detection bias in unblinded studies
Confounding by indication
-indication for drug or severity of disease predicts use of drug
-ex: ACE preventing MI in pt w HTN (HTN pt w comorbidities like DM are more likely to get ACE than other pt)
-ex: COXIBs and GI bleeds (coxibs reserved for people with higher GI bleed risk, so they might not cause GI bleed, pt just might have ulcer or smth already)
-occurs when risk of event is related to INDICATION for med use but not the use of the med itself
-appears when the REASON of rx is associated w outcome of interest
Selection bias
-bias related to procedures used to select subjects/influence study participation
-due to systematic diff in pt selected for study vs pt not selected
Referral bias
-reason for encounter related to drug treatment
-ex: use of drug contributes to diagnostic process
healthy user effect
-access to health care resources have higher level of education
-those who are adherent are healthier
Protopathic bias
-using drug to treat manifestation of undx disease, but drug may actually cause disease
-ex: antipsychotic started to tx delirium but anticholinergic effects contribute to delirium, NSAID for GI pain that turns out to be ulcer
-“reverse causality”
-occurs if tx was stared, then stopped or changed bc baseline manifestation caused by disease or other outcome event
-occurs when the drug is initiated in response to first sx of disease while still technically undiagnosed
-different than confounding by indication which is when risk is related to indication, not medication
Misclassification effect
-classify patient wrong
-missing data also a prob
Prevalence bias
-prevalent cases rather than new (incident) cases are selected
-need to make sure we’re selecting pt that don’t have abnormal baseline for what side effect we’re looking for
time related biases
-lag time
-immortal time bias
Lag time bias
-ex: PPI in fracture risk
-delayed time to see drug to start working
immortal time bias
-period of follow-up when outcome being studied could never occur
-if pt died before receiving heart transplant, they were defaulted to non-transplant
-so theres a time between waiting for transplant where transplant group is “immortal” until transplant
-pt in late initiation group had to be inhospital for at least 7 days to be in that group
Pharmacovigilance
-CONTINUAL monitoring for unwanted effects and other SAFETY aspects of marketed drugs
-detect, evaluate, understand ADR postmarketing
-wider use of data
Pharmacovigilance programs
-FDA adverse event reporting system (FAERS): receives postmarketing ADR reports
-FDA Sentinel System: monitor safety of FDA products
-FDA vax adverse event reporting system (FDA VARES)
-FDA started v-safe after covid for ppl to self-report vax adrs
Pharmacovigilance data use
-post-marketing surveillance
-signal detection
-data mining (social media)
-often regulatory agencies and industry (FDA)
-get data on pt excluded from premarketing studies, ADRs, similar to phxepi
phxepi vs pharmavigilance
-epi: more hypothesis driven, discrete studies
-vigilance: more ongoing, continuous processes
Comparative effectiveness research (CER)
-studying interventions in real world settings
-determine what therapeutic intervention (not just drug products) works best for a given disorder in patients likely to be seen in clinical practice
-conduct of research comparing interventions
-multiple study designs rct and observational
-efficacy (ideal) vs effectiveness (real)
-focus on effectiveness
