Primary Care's 2014 Lessons: The Research Changing Practice

Linda Brookes, MSc

Disclosures

December 18, 2014

In This Article

Pneumococcal 13-Valent Vaccine in Older Patients

In March, clinical trial data were released confirming the efficacy of the pneumococcal 13-valent conjugate vaccine (diphtheria CRM197 protein) (Prevnar 13®) in older adults. The results of the Community Acquired Pneumonia Immunization Trial in Adults (CAPiTA), presented during the 9th International Symposium on Pneumococci and Pneumococcal Diseases (ISPPD), showed that PCV13 reduced first episodes of vaccine-type pneumococcal CAP (VT-CAP) by 45.56% (P = .0006 vs placebo) in patients ≥ 65 years.[23,24] Vaccination also reduced first episodes of nonbacteremic/noninvasive VT-CAP by 45.00% (P = .0067) and first episodes of VT invasive pneumococcal disease (VT-IPD) by 75.00% (P = .0005). The safety profile of PCV13 was consistent with previous studies conducted in adults.

This randomized, double-blind trial was a postmarketing requirement following the accelerated approval of PCV13 for use in this age group by the FDA in 2011.[25] The Centers for Disease Control and Prevention's (CDC) Advisory Committee on Immunization Practices (ACIP) deferred its recommendation until the CAPiTA data became available[26] ACIP now recommends that all adults aged ≥ 65 years should routinely receive both PCV13 and the other FDA-approved pneumococcal vaccine, pneumococcal polysaccharide vaccine (PPSV) 23 (Pneumovax® 23) in series.

CDC researchers later reported that applying the efficacy estimates from CAPiTA to the US population indicated that vaccination with PCV13 in 60% of adults aged ≥ 65 years would prevent 1600 cases of IPD and 32,700 cases of inpatient CAP annually.[27]

Aspirin for Primary Prevention: The Debate Goes On

In women, as in men, the use of aspirin is approved in secondary prevention of CV disease, but its role in primary prevention has remained uncertain, with only moderate benefits reported at the cost of major gastrointestinal (GI) bleeding. The Women's Health Study (WHS) initially reported that in healthy women, aspirin lowered the risk for stroke without affecting the risk for myocardial infarction or CV mortality.[28] Use of aspirin is recommended in the primary prevention of ischemic stroke, provided that the potential benefit outweighs the potential harm due to an increase in GI hemorrhage.[29] Recent studies suggesting that low-dose aspirin reduces cancer risk, particularly colorectal cancer, may support its increased use,[30] although the WHS did not show any protective effect against cancer.[31]

The first analysis of the combined benefits for cancer and cardiovascular disease (CVD) in women was reported from 27,939 healthy women in the WHS.[32] Use of low-dose (100 mg) alternative-day aspirin was found to be ineffective as primary prevention or was even harmful in the majority of women. Although aspirin was associated with a small 15-year absolute risk reduction (ARR) in CVD (0.27%) and colorectal cancer (0.14%), the risk for GI bleeding was increased by 0.75%, resulting in an overall increase in risk for all outcomes of 0.75%. A stronger protective effect of aspirin on CVD (ARR 3.11%) was seen in women aged ≥ 65 years, confirming previous findings from the WHS,[33] although the excess risk for major GI bleeding also increased with age. The study concluded that selective treatment of women ≥ 65 years may improve net benefit compared with treating everyone, no one, or prediction-based treatment.

Many commentators and the FDA have stressed the need to wait for the results of randomized clinical trials before drawing any conclusions about aspirin use in primary prevention. The Japanese Primary Prevention Project recently reported no significant reduction in total CV events with aspirin in men or women.[34,35] The results of other trials are expected within the next few years.

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