• Some kidney stones-related facts

    I’ve done some reading. Here are a few kidney stones-related facts from the literature:

    • 13% of men and 7% of women get kidney stones in their lifetimes, though often asymptomatically. Source: Fink et al. (2013).
    • There have been just two RCTs on the effect of increased water consumption on recurrence of kidney stones. One found an effect and the other didn’t. Observational studies suggest a benefit. Though this is a thin base of evidence to go on, increased water consumption does no harm. About 3 liters per day (or about 12.5 cups) is recommended. Sources: Fink et al. (2013)Bao (2012).
    • Since most kidney stones are of the calcium oxalate type, many stone makers may be interested in a low-oxalate diet. Very good resources for oxalate content of foods are here (via Goldfarb and Nazzal (2013)). More kidney stone diet info here, though such things are not hard to find.
    • It appears as if I was dosed with narcotics at the ED unnecessarily during my bout with the stone. A Cochrane review found that NSAIDs work just as well as opioids for renal colic and have fewer complications. Notice that this is not the kind of thing an empowered and/or savvy consumer could easily discover at the time of treatment. I am savvy, but I was in no condition to conduct research or question the practitioner. The drug was generously given and gratefully received. That is, I was a satisfied patient. Nevertheless, evidence suggests, it was the wrong drug. There’s only so much a consumer can do about clinical- vs. satisfaction-type quality.


    • As someone who has treated many patients with kidney stones, I appreciate your first-person account and I’m glad you’re feeling better! I would like to make two quick points:

      First, I would avoid saying ‘increased water consumption does no harm’ as a standalone sentence (although the amount you specified in the next sentence shouldn’t cause problems). I have personally treated a patient who was told to drink lots of water after having kidney stones and who ended up drinking his sodium level down so low that he started having seizures and required intubation and ICU admission. Most of the time you’re right, more water is fine. But if a patient, particularly a patient on an atypical diet or one taking a medication that affected their ability to excrete or conserve sodium or water, was drinking lots of water and starting to feel lousy, I wouldn’t want them to tell themselves ‘increased water consumption does no harm’ and press on.

      Second, I think the Cochrane findings’ bearing on your treatment were probably more nuanced than your account suggests. It was gated so I could only read the summary, but it looks like there was a lot of heterogeneity in the results with the vast majority of the opioid-related problems associated with the use of demerol in particular. Demerol is rarely used in EDs now (at least in my experience) so I’m going to guess you didn’t get it although I could always be wrong. Also, I would guess that you likely did get an NSAID as well. Ketorolac, an NSAID, is commonly given in the IV at the same time as the opioid; for obvious reasons, however, the ketorolac isn’t the drug that patients remember. I couldn’t tell whether the Cochrane review compared a combo of a non-Demerol-narcotic-and-NSAID combo to an NSAID alone, but that’s really the comparison of interest for most of the places where I’ve worked.

      So generally the point I am trying to make is that being an informed consumer of healthcare is really hard: even common-sense advice can go wrong (rarely, but with spectacularly bad results), and what looks like a straightforward recommendation from an impeccable source can turn out to have important caveats. (Feel free to correct my assumptions if your record says you got demerol alone, of course.)

      • I got demerol. I did get an NSAID as well. I think we both agree that it is hard for a consumer to know whether the practitioner is following the best evidence.

        Quoting the Cochrane report:

        Single bolus doses of both NSAIDs and opioids provide pain relief to patients with acute renal colic. However, patients receiving NSAIDs achieve greater reduction in pain scores and are less likely to require further analgesia in the short term. Opioids are associated with a higher rate of vomiting than NSAIDs and this is particularly true for pethidine. Given these findings, then a single bolus of analgesia is used we recommend an NSAID rather than an opioid If opioids are to be used either because of contraindications to NSAIDS or ease of titratibility, we recommend that it should not be pethidine given the high rate of associated vomiting.

        If you email me, I will send you the report.

    • Completely agree “it is hard for a consumer to know whether the practitioner is following the best evidence.” This is particularly important because it’s fair to say that you (Austin) are a very informed consumers. There are a lot of people out there pushing consumer choice very hard, in in every aspect of health care. I’m all for the consumer to be involved but frequently it’s not reasonable or even possible.

    • Having gone through it once (not so great ER in middle of night; semi – trained nurse could not find a vein and I have big veins and thank god it passed in about 3 hours worst pain EVER) I can only add on a personal note that “just give me morphine!” seemed a very reasonable consumer response at the time.

    • Rather interesting that of the 20 included studies in the Cochrane review, only 3 were done in the USA. Cochrane rarely puts the national setting of the included studies in its summary tables, but it was an interesting feature of this review.

      I wonder why so few of the clinical trials were conducted here.