Hi Sestini,

 

My PICO formulation pertains to “Direct” evidence about effectiveness (and harms) of testing. In this case the test becomes more like a treatment intervention. Such evidence usually does not exist particularly in RCTs. But this is the most important question given the equipoise originally posed (i.e. whether an urine stick for nitrite/leukocyte esterase could be useful to guide antibiotic therapy).

Anticipating that this evidence would not exist or will be grossly underpowered…one could answer this indirectly. The searches you employed pertain to indirect evidence I suspect. And indirect line of questioning to answer this equipoise would be:

 

·         What is the comparative effectiveness and harms of early empiric antibiotic treatment of women with suspected cystitis?  

·         What is the diagnostic performance of urine stick for nitrite/leukocyte esterase for ruling out bacterial cystitis in these women?

·         Given the estimates of urine stick test accuracy (which should be translated into population level True positive, True negatives, False positive and False negatives), is prior testing likely to reduce unnecessary antibiotic treatment without causing unnecessary harms?

·         What is the evidence for comparative effectiveness and harms of treating symptomatic women negative for bacterial cystitis with antibiotic therapy (assuming that anecdotal evidence indicates that antibiotics are helpful because reasons other than their bacteri-cidal/static actions).

 

Or maybe I just didn’t get the original concern.

 

m

 

I find the cystitis vignette very interesting. For the question “whether an urine stick for nitrite/leukocyte esterase could be useful to guide antibiotic therapy” my attempt at PICOs is below. In my opinion the question posed above is about effectiveness of point-of-care testing. I’d be interested in learning how further refinements change my provisional (non-expert) PICOs.

 

Population: Non-pregnant, sexually active, adult women (several population subgroups could be potential effect modifiers) with symptoms of cystitis (but not pyelonephritis) in primary care settings

Intervention: management guided by results of urine stick for nitrite/leukocyte esterase (should be different for test positives, negatives, and those categorized as inconclusive)

Comparator 1: No testing, but early empiric antibiotic treatment of all

Comparator 2: No testing, and no initial empiric antibiotic treatment (delayed treatment if indicated)

Comparator 3: No testing but early empiric antibiotic treatment at physician’s discretion

Outcomes: time to symptom resolution (with an additional comparison between test positives and comparators 2 & 3) ; incidence of complicated cystitis/pyelopnephritis (with an additional comparison between test negatives and untested patients); and major adverse events (with an additional comparison between test negatives and untested patients)  

 

Study designs: RCTs or comparative observational studies.

 

The last time I did a search on this topic, I found studies on the effectiveness of antibiotics in dipstick-negative women, but not in dipstick positive ones (they were prescribed antibiotics as the probability of a bacterial infection was considered high).
Thus, "best available evidence" depends on what information is there, more than the throughoutfulness (not sure that this word actually exists) of the question: the point is how to find it.
I usually prefer a bottom-up question: starting with a very generic question (cystitis AND dipstick AND antibiotics), then refine it if the yield is high.   Of course you can also use a top-down strategy, starting with a more demanding question and reducing your requirements as you don't find what you want.
It also depend from expertise, that is your personal knowledge of the field (which in this case, for me, is admittedly low), that is, before a PICO question can be assembled, one or more background questions should be often asked, particularly by the non-expert.

cheers,
piersante sestini

 

Hi Piersante,

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