Clinical Briefs by Louis Kuritzky, MD
Clinical Briefs
By Louis Kuritzky, MD, Clinical Assistant Professor, University of Florida, Gainesville. Dr. Kuritzky is a consultant for Sucampo Pharmaceuticals, Takeda, Boehringer Ingelheim; and is a consultant and on the speaker's bureau for Novo Nordisk, Lilly, Daiichi Sankyo, Forest Pharmaceuticals, Cephalon, Novartis, and Sanofi Aventis.
Recent insights into lactose intolerance
Source: Gaskin DJ, Ilich JZ. Lactose maldigestion revisited: Diagnosis, prevalence in ethnic minorities, and dietary recommendations to overcome it. Am J Lifestyle Med 2009;3:212-218.
Nelson textbook of pediatrics reports that lactase deficiency (LAC) occurs in 15% of whites, 40% of Asians, and 85% of blacks. Activity of lactase decreases with age. Additionally, LAC may be inherited or acquired.
Although there is some support for diagnosing LAC by response to a dairy-free diet, specific testing hydrogen breath tests (believed to be the test of choice), lactose tolerance test, stool acidity test can confirm the diagnosis.
Symptoms of LAC are usually dependent upon the dose of lactose: In 1 report, 20-30% of LAC subjects developed symptoms after drinking 1 glass of milk, increasing to 50% after 2 glasses. At a threshold of 50 g lactose (about four 8-ounce glasses of milk), all subjects were symptomatic.
Not everyone who perceives themselves to be lactase-deficient is: Of 40 teenage girls reporting symptomatic LAC, only 18 were confirmed by hydrogen breath testing. Perhaps not surprisingly, the BMD of self-diagnosed LAC was lower than that of the control group, corroborating the potential skeletal health consequences of dairy avoidance.
Probiotic treatment has been shown to favorably affect symptoms. In a study of Chinese subjects with LAC, Bifidobacterium animalis improved symptoms. Lactase supplements, taken 30 minutes prior to lactose ingestion, reduce but may not totally resolve symptoms. Osteoporosis remains a prominent global problem. Better management of LAC may reduce risk for osteoporosis.
Tamsulosin and ophthalmic surgery
Source: Bell CM, et al. Association between tamsulosin and serious ophthalmic adverse events in older men following cataract surgery. JAMA 2009;301:1991-1996.
By age 70, most men have BPH, for which a-blockers (e.g., tamsulosin, alfuzosin, terazosin, doxazosin) commonly provide symptomatic relief. Alpha receptors, the site through which prostate and bladder symptoms are believed to be ameliorated, are also present in the iris. At ophthalmic surgery, mydriasis is dependent on activation of the iris smooth muscle dilator muscle, which can be blocked by tamsulosin, resulting in intraoperative floppy iris syndrome (IFIS).
Drawing upon a database of senior men who had undergone cataract surgery between 2002 and 2007 (n = 96,128), adverse ophthalmic outcomes (retinal detachment, lens fragmentation or displacement, or endophthalmitis) within 14 days of surgery were compiled. Comparisons were made between men who did and did not receive a-blockers, with further comparison of tamsulosin vs other a-blockers.
Overall, postoperative adverse events were rare (0.3%). Nonetheless, the odds ratio for an adverse event was more than 2-fold higher in subjects treated with tamsulosin, and was not seen with other a-blockers. The increased risk for postoperative adverse events was limited to subjects receiving tamsulosin within 14 days of surgery; past users (> 14 days) of any a-blocker, including tamsulosin, had no greater risk.
Aspirin for primary prevention of CV events
Source: Antithrombotic Trialists Collaboration. Aspirin in the primary and secondary prevention of vascular disease. Lancet 2009;373:1849-1860.
Because studies of secondary prevention of CV disease contain a preselected, very high-risk group, risk reduction is more readily demonstrated than in a primary prevention population. The relative merits (or lack of same) of aspirin for primary prevention could readily confuse even the most stalwart clinician-scientist, since august consensus groups have offered widely divergent opinions based upon the same data.
The Antithrombotic Trialists Collaboration is perhaps the most widely recognized group to provide advice about aspirin treatment. In their most recent publication addressing aspirin for prevention of vascular disease, they analyzed data from 95,000 individuals in clinical trials for primary prevention.
For primary prevention, there was a reduction of CV events from 0.57%/year to 0.51%/year (a 12% relative risk reduction; P < 0.05); reduction in stroke was not significant. This 0.06%/year absolute risk reduction in CV events was offset by an absolute increase in risk of 0.03%/year in major bleeding. Perhaps most important is that although vascular events were reduced, vascular death was not significantly affected. The authors conclude: "In primary prevention ... aspirin is of uncertain net value as the reduction in occlusive events needs to be weighed against any increase in major bleeds."
Aspirin reduces the risk for myocardial infarction in men ages 45-79 and for stroke in women ages 55-79; however, its use must be balanced against the increased risk of serious bleeding events in each individual patient.Subscribe Now for Access
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