And an excellent example of why coding dichotomous as 1/0 instead of Y/N, T/F or similar character coding schemes.
Another approach might be to just do the sum and use a format to create groupings on a single value such
proc format;
value disease2groups
0,1 = '0 or 1'
2-high ='2 or more'
;
value disease3groups
0,1 = '0 or 1'
2,3 = '2 or 3'
4 - high = '4 or more'
;
run;
Then use the format at the time of use for which grouping is desired on the sum variable.
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