Streptococcus pneumoniae: Epidemiology, Risk Factors, and Strategies for Prevention

Joseph P. Lynch, III, MD; George G. Zhanel, PhD


Semin Respir Crit Care Med. 2009;30(2):189-209. 

In This Article

Risk Factors for Mortality in Pneumococcal Pneumonia

Mortality for bacteremic pneumococcal pneumonia ranges from 10 to 30% in adults and < 3% in children.[2,6,10,11,17,250] Case fatality rates for meningitis range from 16 to 37% in adults[8,34] and 1 to 2.6% in children.[34,251] Extrapulmonary manifestations will not be further addressed here. Mortality rates are much higher in the elderly and patients with comorbidities. Although disparate results have been noted, factors associated with higher mortality in bacteremic pneumococcal pneumonia include age (> 65 years),[2,5,11,12,13,15,252,253] multilobar involvement,[2,12,14,252,254] renal failure,[11,12,17] leukopenia,[14,252,255,256,257] alcohol abuse,[6,257] immunosuppression,[5] chronic cardiac disease,[11,17] malignancy,[17] chronic pulmonary disease,[2,254] residence in a nursing home,[2] serious underlying disease,[5,14,15] need for intensive care unit (ICU)[6] or mechanical ventilation,[2,253] shock,[14,257] high acute physiology scores,[2] severity of disease,[15] and treatment with parenteral nutrition.[253] Discordant therapy was associated with higher mortality in some[254,258] but not all[5,259,260] studies. The impact of antimicrobial resistance and discordant antibiotic therapy is discussed in depth in the next article. HIV-infected patients have lower mortality in some studies,[14] likely due to younger age. However, when patients were stratified by clinical status, patients with AIDS had far higher mortality than HIV-infected persons without AIDS.[17,174,211,215] Interestingly, in a prospective, international study of IPD in adults, rigors and chest pain were associated with a lower mortality.[15]

Clinical features of pneumococcal pneumonia are reviewed in detail elsewhere.[1,6,10] We will limit our remarks to changes in the clinical presentation of pneumococcal pneumonia within the past few years (concomitant with the use of PCV7). Recent studies cited a marked increase in pneumococcal empyemas[44,47,261,262,263] and necrotizing pneumonias[37,45,262,264] in children, which reflects replacement by non-PCV7 serotypes (particularly serotypes 1, 3, and 19A).[37,261,265,266]


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