A retrospective study on serum vitamin levels and their clinical implications in hospitalized patients with five kinds of common major chronic diseases

Interventions: Observation group:None Primary outcome(s): Serum vitamin A levels;Serum vitamin B1 levels;Serum vitamin B2 levels;Serum vitamin B6 levels;Serum vitamin B9 levels;Serum vitamin B12 levels;Serum vitamin C levels;Serum vitamin D levels;Serum vitamin E levels Study Design: Cross-sectional