were you given any lectures on this at school? you need to follow the format that your instructors are requiring.
the three part nursing diagnostic statement is the one that most nursing programs want their students to use. it's format is this:
(nursing diagnosis) related to (related factors) as evidenced by (defining characteristics)
an example of a three part nursing diagnostic statement would be as follows:
impaired verbal communication r/t facial muscle spasticity aeb physical difficulty forming words, slurring of words and drooling
to use the terminology "secondary to" is to add a qualifier to the related factors. an example of using this would be to take the same nursing diagnosis above and adding this to it:
impaired verbal communication r/t facial muscle spasticity secondary to cerebral palsy aeb physical difficulty forming words, slurring of words and drooling
note that what is included in this "secondary to" statement is a medical diagnosis. the cardinal rule of nursing diagnosis writing is that no medical diagnoses are to be used. however, some nursing educators allow the use of this additional statement in order to help illustrate the rationale of what is going on here. in the above case the facial muscle spasticity is due to the cerebral palsy and is the cause of the defining characteristics. is is a kind of double check for the student to verify that everything in this nursing diagnostic statement is related. the patient's actual assessment data was the physical difficulty forming words, slurring of word and drooling. the cause of these was the cerebral palsy. however, nurses can't use a medical diagnosis in their nursing diagnosis statements. the better language (and this comes straight out of nanda) is to use facial muscle spasticity.
another example is:
activity intolerance r/t imbalance between oxygen supply and demand aeb dyspnea and the need for oxygen supplementation for an hour after physical therapy
with the "secondary to" statement added to it:
activity intolerance r/t imbalance between oxygen supply and demand secondary to chronic obstructive pulmonary disease aeb dyspnea and the need for oxygen supplementation for an hour after physical therapy
i would not recommend that you use the "secondary to" statement in your nursing diagnosis statements unless your instructors have told you to do this or you have asked them about it first.