Well you know the drill. This is dry I suspect but I love numbers.....
How to predict Vasculitis with Sjögren’s
In the previous article it was stated that 9% of SS patients but that was with a particular set of variables So in the course of your diagnoses there are a number of tests and other evaluations done.
In an extensive study a large group of patients with a average age at the onset of sicca symptoms of 54.7 yrs, an average age at the time of diagnosis of 56.9 yrs and a total follow-up of 2303 patient-yrs (average 8.66 yrs/patient), the following was determined
If you have Parotid scintigraphy grades III or IV, it means you are 4 times more likely to have vasculitis than someone with SS who has a lower Parotid scintigraphy. The prediction will only be wrong 2 times out of a hundred.
If you have Systemic involvement, you are 3 times times more likely to have vasculitis than someone with SS who does not. The prediction will only be wrong 7 times out of a thousand.
If you have Anti-Ro/La antibodies. You are 2 times more likely to have vasculitis than someone with SS who does not. . The prediction will only be wrong 5 times out of a hundred.
If your RF ≥ 25 UI/L You are 2.3 times more likely to have vasculitis than someone with SS who ratio is less. The prediction is virtually unlikely to be wrong..
If your C3 levels <0.82 g/l You are 4 times more likely to have vasculitis than someone with SS who ratio is less. The prediction will only be wrong 3.4 times out of a hundred.
If your C4 levels <0.11 g/l You are 7.5 times more likely to have vasculitis than someone with higher C4 values, with virtually no chance of the prediction being wrong
If you have Cryoglobulins You are 5.4 times more likely to have vasculitis than someone who does not, with virtually no chance of the prediction being wrong
Just because I like numbers this is where the conclusions above came from. Univariate Cox regression analysis identified the following variables at diagnosis associated with the development of vasculitis:
- Parotid scintigraphy grades III or IV with a Hazard ratio of 4.03, P = 0.025
- Systemic involvement with a Hazard ratio of 3.01, P = 0.007
- Anti-Ro/La antibodies with a Hazard ratio of 2.21 P = 0.049
- RF ≥ 25 UI/L with a Hazard ratio of 2.37 P = 0.034
- C3 levels <0.82 g/l with a Hazard ratio 4.05 P = 0.012
- C4 levels <0.11 g/l with a Hazard ratio HR 7.53 P < 0.001
- Cryoglobulins with a Hazard ratio 5.44 P < 0.001
Clear as mud right? A hazard ratio means how likely something is to happen 1 means that chances are the same a ration of 4 means it happens 4 times more often. A p value is how likely it is to be wrong. Because they are Univariates it means that whether you have one are all seven you are no more likely to get Vasculitis
The first set of numbers called univariates are all independent of each other meaning whether you have one or all of them, your chance of getting vasculitis are only as high as the highest hazard ratio.
Vasculitis involved the peripheral nerves in 68% of patients, the skin in 52%, kidneys in 12%, small bowel in 8% and pancreas in 4%. When a biopsy specimen was obtained, the main histological diagnosis was small-vessel vasculitis in 80% (leucocytoclastic in 70% and lymphocytic in 10%) and medium-sized vessel vasculitis (necrotizing vasculitis) in the remaining 20%.