The 1-year incidence of serious adverse events was 31.6 % ( 95 % CI , 12.6 % to 56.6 % ) for MSCs , 31.6 % ( 95 % CI , 12.6 % -56.6 % ) for BMCs , and 38.1 % ( 95 % CI , 18.1 % -61.6 % ) for placebo .