The higher mortality rate in labor camps in 1933 would definitely be influenced by the famine, which hit its acute phase in 1932-1933.

However, another aspect that influenced this higher rate is that the Soviet government massively expanded the number of labor camp inmates in 1932-1933 as well: this was when peasants could be arrested and sentenced to years of hard labor for "theft of state property" (ie gleaning grain from fields) under the so-called Law of Spikelets, but there also was a country-wide plan to introduce passports for legal urban residents, and to crack down on "criminal, socially dangerous and parasitic elements" in cities.

The OGPU (predecessor to the NKVD) developed a plan whereby two million people arrested in these sweeps would be removed to Siberia and Kazakhstan (a million to be sent to each) in early 1933, and put to work in settlements conducting agricultural work, fishing and cottage industries. The plan was that these settlements were to be economically self-sufficient, and would be run like the special settlements that kulaks and their families had been deported to during Dekulakization and collectivization in 1929-1930.

When local party leaders were informed of this plan in early 1933, they balked, with Robert Eikhe, party boss in West Siberia, writing directly to Stalin stating that the plan was unrealistic. After haggling, the OGPU agreed to cut the numbers to a million resettled prisoners, and the Politburo ratified the overall plan in April.

This nevertheless, even at reduced levels, meant a huge influx of prisoners, and a widespread reorganization of the camp system, with there to be some 2 million total inhabitants of the special settlements (including both the new prisoners and the previously-relocated kulaks who had not yet escaped), and some 330,000 inmates of labor camps, who were the hardened criminals or political prisoners.

On top of this, delays in implementing the new settlement plan and its agreed figures did not mean delays in mass arrests, with the result that prisons had filled to three to ten times their normal population, and exactly at a time when the famine and epidemics were at their worst. OGPU inspectors in Ukraine and the North Caucasus noted in March that inmates were receiving 200 grams a bread a day if working, 100 grams if non-working, and 50 grams if sick, with "healthy prisoners" receiving nothing but personal parcels from family members, which given the famine in the regions, were not forthcoming at all. Abuse and misconduct by prison administrators exacerbated the issue.

Long and short, the 1933 figures don't just reflect the worst part of the 1931-1933 famine, but also show how inadequately equipped the Soviet prison system already was to look after the welfare of its inmates, especially in a period when the OPGU was planning additional mass purge campaigns and conducting mass arrests.

Source: Oleg Khlevniuk. The History of the Gulag: From Collectivization to the Great Terror