David GoldfarbDoctor David Goldfarb is a recognized authority on medical prevention of kidney stones, and has played a very important international role as an expert and brilliantly informed advocate for high quality care of the millions of patients with this disease.

The American College of Medicine, through its organ – The Annals of Internal Medicine – is known for publishing excellent guidelines that primary care physicians can use in their practices to achieve a reliable quality of outcomes.

Here we have come upon a true conflict between experts like Dr. Goldfarb and the College of Medicine. He was chosen, by right of his expertise, as a peer reviewer of the defective guidelines the College promulgated last fall, improper and misleading guidelines for stone prevention by changes of diet and use of medications. He rejected the work as technically flawed and exhibiting the defects that arise when ignorance is coupled to public authority. The work was published despite his rejection, an odd and unusual response of a fine journal.

More: David had worked on guidelines promulgated by a far more important and better informed source, the American Urological Association, which speaks with genuine authority and experience for the very physicians who care for stone patients and are trained as part of the certification to conduct such treatment – the real experts in fact. These AUA guidelines are outstanding in that within the limitations of the science available they offer physicians a realistic way of managing care for patients that appears sound and unlikely to do harm.

That his negative review held no sway is unfortunate, and a surprise.

Dr. Goldfarb has chosen to respond to the College in a way that seems to me just, proper, and responsible, and he offered his letter for publication here, on this site which reaches the kidney stone research community, expert physicians in the field, and many of the patients and their families who must view with considerable consternation such confusions and disregard among experts concerning their care.

Here is his personal introduction to the matter, followed by his letter.

Introduction to the ACP Guidelines Problem

In 2012, the Agency for Heathcare Research and Quality (AHRQ), part of the U.S. Department of Health and Human Services, issued a report entitled “Recurrent Nephrolithiasis in Adults: Comparative Effectiveness of Preventive Medical Strategies. The report documented the relative paucity of clinical trials that constitute the body of evidence regarding appropriate strategies for kidney stone prevention. Based on that evidence, two groups endeavored to turn the AHRQ report into clinical guidelines. Each took very different approaches to their projects.  In November 2014, the Annals of Internal Medicine published “Dietary and pharmacologic management to prevent recurrent nephrolithiasis in adults: a clinical practice guideline from the American College of Physicians.” The publication followed shortly after the Journal of Urology’s publication of “Medical management of kidney stones: AUA guideline.” As a participant in, and vice-chair of the AUA guidelines committee, chaired by Dr. Peggy Pearle, I was pleased with our result and disappointed with that of the American College of Physicians, an organization of which I have long been a proud member. Their clinical guidelines are approved by the ACP’s Clinical Guidelines Committee, and then by the ACP’s Board of Regents. In the following letter to the ACP and the Annals, I address some of the shortcomings of the ACP guidelines.

Letter to the American College of Physicians


May 9, 2015

Wayne J. Riley, MD, MPH, MBA, MACP, President, Board of Regents:

Tanveer P. Mir, MD, MACP, Chair, Board of Regents:

Andrew Dunn, MD, FACP, Chair, Board of Governors c/o

Steven E. Weinberger, MD, FACP, Executive Vice President/Chief Executive Officer:

Mary Ann Forciea, MD, FACP, Chair, Clinical Guidelines Committee, c/o

Thomas D. Denberg, MD, PhD, FACP, Immediate Past Chair, Clinical Guidelines Committee


Christine Laine, MD, MPH, FACP, Editor in Chief, Annals of Internal Medicine,

Re: ACP and Kidney Stones

Dear ACP Colleagues,

I would like to express my distress regarding the ACP’s recent issuance of guidelines regarding the medical management of kidney stones.(1) This document does not serve ACP well, nor does it do anything positive for the care of the neglected population of people afflicted by kidney stones.

I recognize that “expert opinion” is currently in disrepute in this era of evidence-based medicine. However, I have a previous history with respect to kidney stones and ACP that is relevant background to this letter. Since 2003, I have been the author of the section of PIER, and then Smart Medicine, entitled Nephrolithiasis. I also authored “In the Clinic: Nephrolithiasis” for Annals.(2)

I then served as a reviewer for Annals for the AHRQ review on kidney stones.(3) I thought that was a valuable work that summarized the evidence regarding kidney stone evaluation and management. I was then invited to write the ACP Journal Club entry on the AHRQ review.(4)

Following that publication, ACP endeavored to develop a set of guidelines regarding prevention of kidney stones. I was asked to review the kidney stones guidelines for Annals. I recommended rejection of the manuscript for many good reasons, and at first it appeared that Annals also rejected it. It was therefore surprising that the paper was eventually published in Annals, without much revision to my eye, and without being sent back to me or (as far as I know) other reviewers. This publication was not of any practical use to practitioners caring for patients with kidney stones.

I understand that these ACP guidelines concentrate exclusively on the results of randomized controlled trials. In the absence of adequate RCT data, an appropriate response might be to not write guidelines at all. Or one could choose instead to acknowledge that in the absence of RCT data, writing guidelines based on “expert opinion” is preferable to nothing, given the clinical need. That is what the American Urological Association’s committee on Medical Management of Kidney Stones decided.(5) I served as vice-chair of that committee and as a representative of the American Society of Nephrology.

It is rather frustrating to read these ACP guidelines in the context of what my goals as a kidney stone doctor are. I try to advance the idea that kidney stones cause significant pain, misery and cost and that they are preventable. The ACP guidelines offer no practical advice that advances this goal. The guidelines do not achieve any utility with respect to diagnosis, evaluation or therapy. As a result they have no pedagogical value: I would not distribute the paper to a resident or a fellow if instruction in the care of patients were the goal.

The ACP guidelines express skepticism about whether kidney stone composition is important; whether 24 hour urine chemistry is worthwhile; and even express uncertainty about whether increasing fluid intake is important. It is true that RCTs have not proven that these tests or therapies are useful. But I disagree that “guidelines” need to be promulgated, leaving practitioners ignorant about what reasonable course should be taken when seeing a patient with stones, when RCTs are lacking. The guidelines suggest that thiazides, allopurinol and citrate may be useful for kidney stone prevention but offer no guidance about how those drugs would be deployed in the absence of kidney stone composition and 24 hour urine chemistry results. Should I give allopurinol to patients with cystinuria? And how would I detect cystinuria if determination of kidney stone composition is of questionable utility? Are thiazides appropriate for uric acid stones? Should potassium citrate be given to some or all stone-formers?

Some of these questions are not ever going to be addressed by RCTs. For instance, I would consider an RCT of citrate therapy for uric acid stones to be highly unethical, given the ease and near 100% efficacy of urinary alkalinization for prevention of these stones. The ACP guidelines fail to make this critical distinction and leave internists dangerously unprepared to take care of this increasingly prevalent and easily prevented stone type.

The painful correspondence from my colleagues around the world after publication of these guidelines included queries about how this publication was possible, and how ACP could publish “garbage” or “a total waste”. At the March 2015 “Consensus Conference for the Metabolic Diagnosis and Medical Prevention of Calcium Nephrolithiasis and its Systemic Manifestations”, held in Rome, discussion about authoring an international dissent regarding the ACP guidelines was a popular topic, demonstrating the worldwide interest in the topic.

Several other points about the ACP document are worth making. None of the authors of the paper have a single other co-authorship in PubMed relevant to kidney stones, other than the AHRQ review. I believe that none of the authors are nephrologists or urologists, none have a kidney stone clinic, none appear at, or present research at, kidney stone meetings, none have any experience regarding management of kidney stones as far as we know. This author list clearly expresses disdain regarding “expert opinion” or perhaps for sub-specialty care. (At least the AHRQ review included one urologist among its authors).

While perhaps ACP regards my participation on the AUA committee as a conflict of interest in voicing these criticisms, I have two other complaints. First, the ACP guidelines failed to cite the AUA guidelines, although the temporal sequence would certainly have allowed that. The ACP document could have said to practitioners, “rather than express ignorance when patients with kidney stones ask you for advice, check out the 36 “expert-opinion-based” recommendations made by AUA; we don’t endorse them but you may find them useful in your practice”. (The ACP guidelines could have also referred internists to Smart Medicine). Second, I was frankly astounded that our letter to Annals (co-authored by the chair and me, vice-chair, of the AUA committee) was not selected for publication (though it remains as a comment on the website. This may be taking ACP’s apparent bias against specialists, or experts, a bit too far.

(And for the record, allopurinol should not be regarded as useful therapy for uric acid stones in the absence of urinary alkalinization, as Qaseem et al suggest in their reply to the letter of Krambeck and Lieske(6): “we are aware that many physicians do select medications based on stone type, for example, allopurinol for uric acid stones, and we do not discourage that practice.”(7) The authors would discourage that practice, as I do, if they were more familiar with the non-RCT kidney stone literature).(8)

I have been proud of my tenure as author of the PIER/Smart Medicine section on stones and assumed that ACP has valued it. Grading recommendations based on the strength of evidence is a strength of that body of work. If it is time to delete most of the opinion-based recommendations I make there, I will sadly have to recognize that times have changed.

The bottom line here is that I consider the ACP guidelines destructive of good medical care of patients with kidney stones. I believe that patient care will be adversely affected. It is possible that third party payers will cease paying for kidney stone composition and 24 hour urine analysis. Urologists and emergency medicine physicians do not routinely practice kidney stone prevention, though they are the practitioners most likely to first see the patients. There is a real potential role for internists then to appropriately manage patients with kidney stones, as they manage patients with diabetes, hypertension and coronary artery disease. Recently, kidney stones have been linked to all three of these co-morbidities through observational and physiological investigations, implying a pathophysiology that may have great import for internists seeing stone formers.(9) Instead, in my experience, internists regard nephrolithiasis as an abstruse field that somehow exceeds their generalist capabilities or as a disorder that produces only a transient, if painful, phenomenon of no consequence.

I cannot argue about the product of the AHRQ review and the relative deficiencies of the RCT-based evidence in lithology; I consider the AHRQ manuscript a useful prod to highlight the need for additional work (and funding). But the ACP’s censoring of expert opinion, and the Annals publishing outside a serious peer-review process, cannot be countenanced as “good practices”. These practices have led to a set of guidelines that I feel are not worthy of ACP, Annals and the internal medicine community.

The opinions offered here are mine alone, and not representative of any other committee or organization.

Yours truly,

David S. Goldfarb, M.D., FACP, FASN

Clinical Chief, Nephrology Division,

NYU Medical Center

Professor of Medicine and Physiology,

NYU School of Medicine

President, ROCK Society 2015-2016

(Research on Calculus Kinetics)


  1. Qaseem A, Dallas P, Forciea MA, Starkey M, Denberg TD. Dietary and pharmacologic management to prevent recurrent nephrolithiasis in adults: a clinical practice guideline from the american college of physicians. Ann Intern Med. 2014;161(9):659-67.
  2. Goldfarb DS. In the clinic. Nephrolithiasis. Annals of internal medicine. 2009;151(3):ITC2.
  3. Fink HA, Wilt TJ, Eidman KE, Garimella PS, MacDonald R, Rutks IR, et al. Medical management to prevent recurrent nephrolithiasis in adults: a systematic review for an American College of Physicians Clinical Guideline. Ann Intern Med. 2013;158(7):535-43.
  4. Goldfarb DS. ACP Journal Club. Review: Thiazide, citrate, or allopurinol reduces recurrence after >/= 2 kidney stone episodes. Ann Intern Med. 2013;159(2):JC12.
  5. Pearle MS, Goldfarb DS, Assimos DG, Curhan G, Denu-Ciocca CJ, Matlaga BR, et al. Medical management of kidney stones: AUA guideline. J Urol. 2014;192(2):316-24.
  6. Krambeck AE, Lieske JC. Prevention of recurrent nephrolithiasis in adults. Ann Intern Med. 2015;162(7):528-9.
  7. Qaseem A, Fink HA, Denberg TD. Prevention of recurrent nephrolithiasis in adults. Ann Intern Med. 2015;162(7):529.
  8. Maalouf NM, Cameron MA, Moe OW, Sakhaee K. Novel insights into the pathogenesis of uric acid nephrolithiasis. Curr Opin Nephrol Hypertens. 2004;13(2):181-9.
  9. Sakhaee K, Maalouf NM, Sinnott B. Clinical review. Kidney stones 2012: pathogenesis, diagnosis, and management. Journal of Clinical Endocrinology and Metabolism. 2012;97(6):1847-60.


  1. Paul

    I’m 35, 103 KG 5,11 over weight. Have had 2 x Calcium Oxalate stones in the past 12 months and had 4 operations (Stent In, Stone Out etc). Common recommendations are less salt and reduce the intake of Oxalate foods. Have read a lot about gut health and bacteria that feed on Oxalate, is there any confidence on this? please source here: Thanks Paul

    • Fredric L Coe

      Hi Paul, Oxalobacter treatments failed. The bacteria need lots of oxalate to live, so if you give them to people they die unless the people eat lots of oxalate. Not a treatment. As for diet and meds, there are trials and very decent prevention protocols. Here is my personal favorite article on the site for this topic. Here is another, more protocolized. They both say to figure out the cause, improve diet, see if that corrects the causes, and add meds if diet is not sufficient. Regards, Fred Coe

  2. physician search San Antonio

    Very useful. Will save this for future reference!

    physician search San Antonio

  3. BILL stanley

    I was struck while doing traffic duty for the Sheriff Dept. I suffered damaged to the central area that control my legs from my waste down. I had to be operated on. During this time I also had bowel difficulty. They discovered kidney stone, over 1 mm in size. they are going to operate. it is 4years since the accident. Could this accident cause this kidney stone problem. I am 67.. Thank You Bill Stanley….. pleae anser

    • Fredric Coe, MD

      Hi Bill, If you had bladder problems that could certainly help promote stones. Likewise if you became immobilized urine calcium would rise and that could promote stones. So yes, it very likely did cause stones. Regards, Fred Coe

  4. Pranav Garimella

    A great read I must admit. Having been closely associated with the AHRQ review and as a ‘young’ nephrologist in practice, I agree that trying to treat patients without characterizing stones or urine chemistry is practically impossible.

    On an unrelated note- I find the posts here very educative and look to catching up with the stone world whenever possible.

    • Fredric Coe, MD

      Hi Pranav, Thanks for the comment. I do wonder what the authors of those guidelines were thinking, or if they were indeed thinking clinically at all. As you say, it would be a practical impossibility to see patients in the ways they recommended. The Annals has shrunk over the years in terms intellectual, a sad progression for what was a flagship journal. Regards, Fred

  5. David S. Goldfarb MD

    Dear Sam,
    OK, I went back and read the ACP guideline very carefully and I believe I am absolutely certain that the guidelines are not useful. I’m very comfortable with, and even agree with, your statement that “expert opinion takes a back seat to evidence”. My letter acknowledges that “expert opinion” is currently in disrepute and I don’t argue with why that is. And that is why I admire the AHRQ review which thoroughly reviewed the evidence and found it lacking. But to quote one of the originators of evidence-based medicine, the late David Sackett: “If no RCT has been carried out, we must follow the trail to the next best external evidence…” The ACP guidelines fail to follow this sensible approach. My suggestion to the ACP after the AHRQ review was that “EBM-based” guidelines were not necessary. But instead of offering some “guidance” they leave the practitioner without any “next best external evidence”. Would you give that document to anyone endeavoring to take care of a recurrent stone former? Could you use the ACP guidelines to prescribe “thiazides, citrate or allopurinol” without first knowing stone composition or determining the 24h urine composition? (And by the way, we are not going to have an RCT of whether knowing stone composition is useful, so let’s just agree to do it since it is inexpensive and harmless. A study of whether 24h urine composition is useful is more imaginable and I could make an argument for treating patients just based on stone composition, though that is not my practice.)
    In summary, one’s response to sparse “evidence” is either to throw one’s hands up in the air and say “I don’t know what to do” which is how I judge the ACP’s response, or to cautiously offer “expert opinion” as the AUA did.
    As for my unseemly self-promotion, I’ll tell you what I think I’m actually doing: I’m trying to promote some useful medical care for my fellow stone-sufferers. I’m replying to all the physicians who did nothing to help recurrent stone formers, who told them to drink “a lot of water” whether they could or not, who did 6 lithotripsies for the patient whose cystinuria was not diagnosed. I want to get primary care practitioners to consider kidney stones like DM, HTN, CHF, CAD: a chronic recurrent condition worth preventing that one does not have to be a renal physiologist to care about. The ACP did not in any way advance the care of this somewhat neglected group of patients. If that seems self-promotional, I happily sign my name to that effort.

  6. Sam Snead

    Goldfarb’s comments are totally off-base. Expert opinion takes a back seat to evidence. He should go back and re-read the ACP guideline very carefully to be absolutely certain he understands the actual scope and what is, and is not, being recommended. He mischaracterizes both of these while making derogatory assertions and engaging in a lot of unseemly self-promotion.

    • Fredric Coe, MD

      Hi, In the spirit of an open university site I am pleased to post your remarks. But in the same spirit, would you please consider identifying yourself as you seem to be an expert in the field and people will want to associate your comments with their maker. Unless you are the famous golfer or share his name. Thanks, Fred Coe

  7. David Sas

    Well done, Dr. Goldfarb.

  8. Mary Tilton


    • Elaine Worcester

      Thank you, David, for a superb itemization of the ways in which the ACP guidelines fail to help either practitioners or patients, and may actually cause harm. I also agree that more trials are needed to further document the efficacy of the kind of thoughtful care you are advocating. In the meantime, I think that where patient care is involved, knowledge is good and careful evaluation of patients is the best medicine.


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