The top hypochondriac fears include fear of disease (disease phobia) and the false belief that you have a disease (disease conviction). Disease phobia was associated with anxiety, while disease conviction was associated with more physical symptoms (Kellner et al., 1992).
Hypochondriacal fears and beliefs, anxiety, and somatisation. Kellner R, Hernandez J, Pathak D. Br J Psychiatry. 1992 Apr;160:525-32.