Seasonal variations in hospital admission for deep vein thrombosis and pulmonary embolism: analysis of discharge data.

Seasonal variation in fatal pulmonary embolism has been well documented by at least 23 reports comprising nearly 11 000 cases.[1] Evidence is lacking, however, for seasonal variation in deep vein thrombosis--the only large hospital series available did not establish significant variation.[2] We analysed hospital admissions for deep vein thrombosis and pulmonary embolism in France over four years.

Methods and results

We reviewed all cases with a discharge diagnosis of deep vein thrombosis or pulmonary embolism entered on the national hospital discharge register between 1995 and 1998. We used the international classification of diseases, ninth and 10th revisions (deep vein thrombosis: ICD-9 codes 451.1 and 451.2 and 1CD-10 codes I80.1 and I80.2; pulmonary embolism: ICD-9 code 415.1 and ICD-10 codes I26.0 and I26.9). This dataset is a collection of all discharges from public and non-profit making, short stay, or acute hospitals in France (71% of hospital capacity). We …