Multiple linear regression analysis revealed age (β = 0.087, P = 0.102), BAS-G (β = 0.181, P = 0.003), fatigue (β = 0.170, P = 0.002), anxiety (β = 0.151, P = 0.002) and nocturnal back pain (β = 0.192, P = 0.001), extra-spinal manifestation (β = 0.120, P = 0.012), and duration of diagnostic delay (β = 0.174, P = 0.001) were the contributors to PSQI.