Elliott M Gomez, Andrea Mustafa, Ilex Beltran-Najera, Natalie R Ridgely, Jennifer L Thompson, Luis D Medina, Steven Paul Woods
Health literacy mediates the association between cognition and healthcare provider interactions among gay and bisexual men with HIV disease
The Clinical neuropsychologist
name suggests evidencebased medicine finding evidence using evidence make clinical decisions cornerstone evidencebased medicine hierarchical system classifying evidence hierarchy known levels evidence physicians encouraged find highest level evidence answer clinical questions several articles published plastic surgery journals concerning evidencebased medicine topics touched subject16 specifically previous articles discussed lack higher level evidence plastic reconstructive surgery need improve evidence published journal accomplished important understand history behind levels interpreted article focuses origin levels evidence relevance evidencebased medicine movement implications field plastic surgery everyday practice plastic surgery history levels evidence levels evidence originally described report canadian task force periodic health examination 19797 reports purpose develop recommendations periodic health examination base recommendations evidence medical literature authors developed system rating evidence table 1 determining effectiveness particular intervention evidence taken account grading recommendations example grade recommendation given good evidence support recommendation condition included periodic health examination levels evidence described expanded sackett8 article levels evidence antithrombotic agents 1989 table 2 systems place randomized controlled trials highest level case series expert opinions lowest level hierarchies rank studies according probability bias randomized controlled trials given highest level designed unbiased less risk systematic errors example randomly allocating subjects two treatment groups types studies also randomize confounding factors may bias results case series expert opinion often biased authors experience opinions control confounding factorstable 1 canadian task force periodic health examinations levels evidencetable 2 levels evidence sackettmodification levels since introduction levels evidence several organizations journals adopted variations classification system diverse specialties often asking different questions recognized type level evidence needed modified accordingly research questions divided following categories treatment prognosis diagnosis economicdecision analysis example table 3 shows levels evidence developed american society plastic surgeons prognosis9 table 4 shows levels developed centre evidencebased medicine treatment10 two tables highlight types studies appropriate question prognosis versus treatment quality data taken account assigning level example randomized controlled trials appropriate looking prognosis disease question instance happen nothing prognosis question involve comparing treatments highest evidence would come cohort study systematic review cohort studies levels evidence also take account quality data example chart centre evidencebased medicine poorly designed randomized controlled trial level evidence cohort studytable 3 levels evidence prognostic studiestable 4 levels evidence therapeutic studiesa grading system provides strength recommendations based evidence also changed time table 5 shows grade practice recommendations developed american society plastic surgeons grading system provides important component evidencebased medicine assists clinical decision making example strong recommendation given level evidence consistent evidence level ii iii iv studies available grading system degrade lower level evidence deciding recommendations results consistenttable 5 grade practice recommendationsinterpretation levels many journals assign level articles publish authors often assign level submitting abstract conference proceedings allows reader know level evidence research designated level evidence always guarantee quality research important readers assume level evidence always best choice appropriate research question concept important us understand evolve field evidencebased medicine plastic surgery design designated surgical specialty always important articles may lower level evidence level innovation technique articles needed move surgical specialty forward although randomized controlled trials often assigned highest level evidence randomized controlled trials conducted properly results scrutinized carefully sackett8 stressed importance estimating types errors power studies interpreting results randomized controlled trials example poorly conducted randomized controlled trial may report negative result low power fact real difference exists treatment groups scales jadad scale developed judge quality randomized controlled trials11 although physicians may time inclination use scale assess quality basic items taken account items used assessing randomized controlled trials include randomization blinding description randomization blinding process description number subjects withdrew dropped study confidence intervals around study estimates description power analysis example bhandari et al12 published article assessing quality surgical randomized controlled trials authors evaluated quality randomized controlled trials reported journal bone joint surgery 1988 2000 articles score greater 75 percent deemed high quality 60 percent articles score less 75 percent authors identified 72 randomized controlled trials time period mean score 68 percent main reason lowquality score lack appropriate randomization blinding description patient exclusion criteria another article found quality score articles journal bone joint surgery level 1 rating compared level 213 therefore one assume level 1 studies higher quality level 2 studies resource surgeons use appraising levels evidence users guides published canadian journal surgery1415 journal bone joint surgery16 similar articles specific surgery published journal american medical association1718 plastic surgery evidencebased medicine field plastic surgery slow adopt evidencebased medicine demonstrated article examining level evidence articles published plastic reconstructive surgery19 authors assigned levels evidence articles published plastic reconstructive surgery 20year period majority studies 93 percent 1983 level iv v denotes case series case reports although results disappointing improvement time 2003 level studies 15 percent fewer level iv v studies 87 percent recent analysis looked number level studies five different plastic surgery journals 1978 2009 authors defined level studies randomized controlled trials metaanalyses restricted search studies number level studies increased one 1978 32 200920 results see field plastic surgery improving level evidence still long way go especially improving quality studies published example approximately onethird studies involved double blinding majority randomize subjects describe randomization process perform power analysis power analysis another area concern plastic surgery review plastic surgery literature found majority published studies inadequate power detect moderate large differences treatment groups21 regardless level evidence study study underpowered interpretation results questionable although goal improve overall level evidence plastic surgery mean lower level evidence discarded case series case reports important hypothesis generation lead controlled studies addition face overwhelming evidence support treatment use antibiotics wound infections need randomized controlled trial clinical examples using levels evidence understand levels evidence work aid reader interpreting levels provide examples plastic surgery literature examples also show peril medical decisions based results case reports association hypothesized lymphoma silicone breast implants based case reports2227 level evidence case reports depending scale used iv v case reports used generate hypothesis possible association existed results several large retrospective cohort studies united states canada denmark sweden finland conducted2832 level evidence retrospective cohort study ii studies many years followup large number patients studies found elevated risk others found risk lymphoma none studies reached statistical significance therefore higher level evidence cohort studies provide evidence risk lymphoma finally systematic review performed combined evidence retrospective cohorts27 results found overall standardized incidence ratio 089 95 percent confidence interval 067 118 confidence interval includes 1 results indicate increased incidence level evidence systematic review based best available evidence association lymphoma silicone implants example shows studies low level evidence used generate hypothesis led higher level evidence disproved hypothesis example also demonstrates randomized controlled trials feasible rare events cancer emphasizes importance observational studies specific study question casecontrol study better option provides higher level evidence testing prognosis longterm effect silicone breast implants another example injection epinephrine fingers based case reports 1950 physicians advised epinephrine injection result finger ischemia33 see example level iv v evidence accepted fact incorporated medical textbooks teaching however physicians accepted evidence performing injections epinephrine fingers adverse effects hand obviously time higher level evidence resolve issue indepth review literature 1880 2000 denkler33 identified 48 cases digital infarction 21 injected epinephrine analysis found addition procaine epinephrine injection cause ischemia34 procaine used injections included toxic acidic batches recalled 1948 addition several cohort studies found complications use epinephrine fingers hand3537 results cohort studies increased level evidence based best available evidence studies hypothesis epinephrine injection harm fingers rejected example highlights biases inherent case reports also shows risk spurious evidence handed integrated medical teaching obtaining best evidence established need randomized controlled trials improve evidence plastic surgery also acknowledged difficulties particularly randomization blinding although randomized controlled trials may appropriate many surgical questions welldesigned wellconducted cohort casecontrol studies could boost level evidence many current studies tend descriptive lack control group way forward seems clear plastic surgery researchers need consider using cohort casecontrol design whenever randomized controlled trial possible designed properly level evidence observational studies approach surpass randomized controlled trial instances observational studies randomized controlled trials yielded similar results38 enough cohort casecontrol studies become available prospect systematic reviews studies increase increase overall evidence levels plastic surgery conclusions levels evidence important component evidencebased medicine understanding levels assigned publications abstracts helps reader prioritize information say level iv evidence ignored level evidence accepted fact levels evidence provide guide reader needs cautious interpreting results acknowledgments work supported part midcareer investigator award patientoriented research k24 ar053120 national institute arthritis musculoskeletal skin diseases kcc