Nonrespiratory determinants of respiratory impairment in elderly patients: heart failure and diabetes.

Heart failure (HF) and diabetes mellitus (DM) promote a plethora of abnormalities in lung function and, in both conditions, the lung is considered the ‘‘target organ’’ for therapeutic interventions. HF is associated with changes in lung mechanics and gas diffusion, which are the direct consequence of haemodynamic perturbations and congestion. Changes in lung mechanics may vary according to the acute or chronic manifestations of HF, with a predominant obstructive lung pattern in acute HF and a restrictive one in chronic conditions. Specific relevance has recently been given to the anatomical and functional consequence of a pressure and/or a volume overload on the lung microcirculation of HF patients. This challenges the alveolar–capillary integrity, causes an increase in capillary permeability to water and ions, and impairs local mechanisms for gas diffusion. Remarkably, an impairment in alveolar gas conductance properties reflects underlying lung tissue damage, is involved in the pathogenesis of exercise limitation and is an independent prognostic marker. Diabetes mellitus elicits an angiopathy process of the lung microvessels that leads to the development of pulmonary dysfunction and to an accelerated organ ageing process. An increasing prevalence of type 2 diabetes mellitus with age indicates that elderly subjects are more exposed to the pulmonary complications of the disease. Diabetes mellitus could also contribute to an increase in the incidence of respiratory infections both by itself and by worsening the age-related abnormalities of the respiratory system. Epidemiological and clinical studies show that diabetes mellitusrelated pulmonary involvement has important clinical and prognostic implications contributing to increased morbidity and mortality of older subjects.