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Background: The purpose of this study was to analyze and determine the prevalence and clinical characteristics of hospitalized dementia patients compared with nondemented patients. Methods: We examined hospital discharge database records dated 1998–2003 from public hospitals in Andalusia, Spain. We used ICD-9-CM codes to identify patients with dementia. The variables examined included age, length of stay, discharge diagnosis, diagnostic-related groups, and mortality of both dementia and nondementia patients over 65 years of age. Results: A diagnosis of dementia was documented for 40,482 cases. The prevalence of dementia increased from 3.43% to 4.64% between 1998 and 2003 and was higher among older patients and women. Dementia was the reason for admission in 5.6% of cases. Medical reasons constituted 82.4% of admittances. Dementia patients had hip surgery more frequently than patients without dementia, and other procedures (orthopedic surgery, cataracts, or hernia repair) were less frequent (p < 0.001). The mean duration of the hospital stay was longer (13.4 vs. 10.7 days) and the intra-hospital mortality rate was greater (19.3% vs. 8.7%) for patients with dementia compared to those without dementia. Dementia was an independent predictor of mortality (OR 1.77; 95% CI 1.72–1.82). Conclusions: Dementia is increasing among hospitalized patients. Dementia patients have different reasons for hospitalization and higher mortality. It is necessary to identify these differences and to improve the hospital care of dementia patients.

Aberrations in the ubiquitin-proteasome system (UPS) are implicated in the pathogenesis of various diseases. Tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamines biosynthesis, is involved in hypertension development. In this study we investigated whether UPS regulated TH turnover in PC12 cells and hypothalamic and brainstem neurons from spontaneously hypertensive rats (SHR) and whether this system was impaired in hypertension. PC12 cells were exposed to proteasome or lysosome inhibitors and TH protein level evaluated by Western blot. Lactacystin, a proteasome inhibitor, induced an increase of 86±15% in TH levels after 30 min of incubation, then it started to decrease up to 6 h to reach control levels and finally it rose up to 35.2±8.5% after 24 h. Bafilomycin, a lysosome inhibitor, did not alter TH protein levels during short times, but it increased TH by 92±22% above basal after 6 h treatment. Before degradation proteasome substrates are labeled by conjugation with ubiquitin. Efficacy of proteasome inhibition on TH turnover was evidenced by accumulation of ubiquitinylated TH after 30 min. Further, the inhibition of proteasome increased the quantity of TH phosphorylated at Ser40, which is essential for TH activity, by 2.7±0.3 fold above basal. TH protein level was upregulated in neurons from hypothalami and brainstem of SHR when the proteasome was inhibited during 30 min, supporting that neuronal TH is also short-term regulated by the proteasome. Since the increased TH levels reported in hypertension may result from proteasome dysfunction, we evaluate proteasme activity. Proteasome activity was significantly reduced by 67±4% in hypothalamic and brainstem neurons from SHR while its protein levels did not change. Present findings show that TH is regulated by the UPS. The impairment in proteasome activity observed in SHR neurons may be one of the causes of the increased TH protein levels reported in hypertension.