Current perspective of the HCAP problem: is it CAP or is it HAP?

The number of individuals receiving health care outside the hospital setting, including home wound care or infusion therapy, dialysis, nursing homes, and similar settings is constantly increasing. One of the most frequent causes of hospitalization and mortality in these patients is pneumonia. Hence a new class of pneumonia has been identified: healthcare-associated pneumonia (HCAP). The last American Thoracic Society/Infectious Disease Society of America (ATS/IDSA) guidelines define specific criteria to identify HCAP; however, the clinical practice suggests that the presence of indwelling devices (permanent catheters, etc.) may also be considered an additional criterion. Different studies have shown that, in comparison with community-acquired pneumonia (CAP) patients, HCAP patients are significantly older, have a higher number of comorbidities (cerebrovascular diseases, congestive heart failure, dementia, and diabetes mellitus) and show worse functional status before admission. It has also been observed that HCAP differs from CAP in terms of clinical presentation, risk factors, etiology, prognostics, and, likely, therapeutic approach. The clinical presentation of HCAP is often unusual because it is frequently conditioned by advanced age, multiple chronic comorbidities, and neurological disorders. Classic respiratory symptoms of pneumonia are often mild in HCAP, whereas extrapulmonary manifestations, including mental confusion and gastrointestinal disorders, are frequent. HCAP patients, commonly present a worse clinical presentation (hypoxemia, altered consciousness, Fine score, multilobar infiltrates, etc.) than CAP, and a mortality rate close to that of hospital-acquired pneumonia. Many studies have attributed these findings to a nosocomial etiology [methicillin-resistant Staphylococcus aureus (MRSA) , Pseudomonas aeruginosa, etc.] with a high frequency of multidrug-resistant infections (MRIs), even though this remains controversial. Further investigation on microbial composition and MRI risk factors of HCAP is fundamental because no definitive therapeutic indications are currently available.